Oral Cavity
 Lips
o Function:
 Help prevent food from going back out of mouth when eating
 Phonition
o Structure/What will help identify it in a microscope:
 Outer surface/external skin region
 Stratified squamous keratinized epithelium
o Contains sebaceous glands, sweat glands, and hair follicles
 Internal surface is mucosal
 Non-keratinized stratified squamous epithelium
o Contains minor salivary glands (labial salivary glands)
o Function:
o What will help identify it in a microscope:
 Cheeks
o Function
o What will help identify it in a microscope:
 Tongue
o Function:
o Structure:
 Epithelial surfaces are underlain by lamina propria and submucosa (dense,
irregular collagenous CT)
 Dorsal surface:
 Stratified squamous parakeratinized to keratinized epithelium
 Ventral surface:
 Stratified squamous non-keratinized epithelium
o What will help identify it in a microscope:
 Bundles of skeletal muscle in three different directions
 Many lingual salivary glands in lamina propia
 Bundles of peripheral nerve fibers
o Epithelial papillae (located on the dorsal surface, more anterior)
 Filiform
 Function:
o Grasp and move food
 How you can identify it:
o Short, narrow, highly keratinized structures
o NO taste buds
 Fungiform
 Function:
o Gustatory – helps you taste
 How you can identify it
o Mushroom shaped
o Non-keratinized stratified squamous epithelium

o Occasional taste buds
Circumvallate
 Function:
o Gustatory
o Primary place for Taste buds
 Intraepithelial structures
 Taste buds are neuroepithelial cells
 Nerve fibers penetrate basement membrane
 How you can identify it
o Surrounded by a moat
o Lie anterior to the sulcus terminalis
o Contains serous (salivary glands)
o Von Ebner glands
 Minor salivary glands
 Deliver serous secretion to taste buds to help wash
them clean
Afferent nerve from cranial nerve 7 or 9
 Teeth
o Function:
o Structure/What will help identify it in a microscope:
 Teeth have an internal soft tissue, pulp and 3 calcified tissues: enamel,
cementum (both form the surface layer), and dentin
 Dental Pulp
o Vascularized CT
o Contains
 odontoblasts in layers closest to dentin
 Fibroblasts
 Mesenchymal cells
 Types 1 and 3 collagen fiber


Afferent nerve fibers (all interpreted as pain)
Dentin
o Surrounds central pulp chamber and pulp (root) canal
o Made by: odontoblasts
o Still made after tooth eruption
o Contains:
 Type 1 collagen fibers
 Cementum
o Made by: cementoblasts
o Still elaborated after tooth eruption
o Contains
 Type 1 collagen fibers
 Calcified matrix
 Enamel
o Made by: ameloblasts
o Cannot be repaired, acellular after tooth eruption
o Contains
 Calcified matrix
o Structures associated with the teeth:
 Periodontal ligament
 Structure:
o Type 1 collagen fibers arranged in 5 principal layers
 Function: suspend bone in alveolus
 Gingivae
 Structure:
o stratified squamous keratinized epithelium
 Function:
 Alveolar bone
 Structure:
o Inner layer of compact bone
o Outer layer of compact bone with intervening layer of
cancellous bone

Pharynx
o Function:
o What will help identify it in a microscope
 Liver
o Hepatocytes
 Functions:
 Intitial processing and storage of products of digestion
 Synthesis of most protein in plasma (but not immunoglobulins)
 Final degredation of components of RBC “disposal”
 Detoxification of drugs, toxins, etc
 Synthesis and secretion of components of bile, also recovery and
recyclying
o Space of disse – subendothelial space between hepatocytes and sinusoidal lining
cells
o Sinusoids
 Where hepatocytes and blood vessels come together
 Blood and bile go in OPPOSITE directions
o Exocrine products:
 Bile (portal lobule)
o Endocrine products:
 Vitamin d – modified here but stored in skeletal muscle
 Thyroxine – used to be T4 in thyroid gland  converted to T3 here
 Growth hormone – modified here can be inhibited by somatostatin
 Insulin and glucagon- degraded here
o Storage products:
 Vitamin a – important for vision  stored in Ito cells
 Vitamin k- helps make prothrombin and clotting factors  travel with
chylomicrons to liver
 Fe – ferried to hepatocyte via transferring  stored in ferritin/converted to
hemosidern
o Contains Kupffer cells:
 Macrophages that clean the blood
 Phagocytose debris not cleared by the spleen
o Flow of bile from canaliculus to duodenum
 Canaliculi  bile duct  hepatic and cystic duct  common bile duct 
duodenum
o Flow of bile from canaliculus to gall bladder
 Canaliculi  bile duct  hepatic duct  gall bladder
 Gall bladder
o Function:
 Stores and concentrates bile
 Does NOT secrete anything
 Absorption
 NO GLANDS
o Difference between bile duct and bile canaliculi?
 Bile duct has its own epithelium
o ONLY 3 LAYERS
 Mucosa – epithelium, lamina propria
 Muscularis externa
 Serosa/adventitia
 Pancreas
o Functions:
 Endocrine AND
 Islet cells (islet of langerhans)
o Secrete insulin and glucagon
o DO NOT secrete into a duct, secrete across a basal
membrane
o Vasculature picks up what they get rid of

Exocrine
 Exocrine acini cells
o Generate pepsin
o Glycoproteins
 Secretions contain
o Water
o Ions
 Potassium, sodium, bicarbonate and chloride
 Alkaline
o Enzymes
 Digestion of food in lumen of small intestine
 Ducts – modify composition of bicarbonate in exchange for
chloride
o Striated ducts
o Intercalated ducts
 Control of pancreatic secretion:
 Hormonal  enteroendocrine cells
 Secretin  ducts, bicarbonate-rich fluid, CCK(Pz), acinar
cells, the various (pro) enzymes
 Neuronal  vagus stimulates acinar cells via Ach, releases VIP
which has secretin-like effects (stimulates ducts). Sympathetic
stimulation inhibits vagal and secretin induced secretion, and via
vasoconstriction, reduces secretion.
 Phases of Secretion
 Resting
 Cephalic – CNS mediated, zymogens and some alkaline fluid
 Gastric – vagal effects and gastrin triggers some additional fluid
from ducts
 Intestinal – hormonal and neuronal stimulation of bulk release
o Most material released prior to intestinal phase do NOT
exit pancreas until secretin effects “kick in”
o Structure:
 Similar to salivary glands
 Contains centroacinar cells – start of intercalated ducts
 Salivary Glands
o Minor
 Labial (lips)
 Buccal (cheeks)
 Lingual (tongue)
o Major
 Acini
o Serous and mucous
o Contain myoepithelial cells
o How to tell the difference between mucous and serous in
slides:



Mucous – paler, nuclei are squashed against basal
surface
Serous – round nuclei, myoepithelial cells
However, mucous and serous cells can often be
seen together
o Ducts:
 Intercalated
 Cuboidal epithelium
 Originate in acini and join to form striated
ducts
 Can deliver bicarbonate ions into secretion
 Striated
 Lined by ion transporting cells that remove
sodium and chloride ions from luminal fluid,
and pump potassium into it
 Converge to form excretory ducts with run
in CT septa
 Excretory
 Largest
 Tall columnar, stratified columnar or
stratified squamous
 Empty into oral cavity




Parotid
 Function: SEROUS
 How to identify:
o Barely and mucous clusters and a lot of fat cells
Submandibular
 Function:
o Secrete mucous and or serous MIXED.
 How to identify:
o Parenchyma/stroma = secretory cells and ducts
 Secretory cells are arranged in clusters (acini)
Sublingual
 Function:
o Secrete mostly mucous with mucous acini capped with
serous demilunes.
Function of all salivary glands:
 Synthesize and secrete salivary amylase, lysozyme, lactoferrin, and
a secretory component, when complexes with IgA to resist
enzymatic digestion in saliva
 Saliva:
o Function:
 Water Moisten
 Mucouslubricate food
 AmylaseInitiate digestion of carbohydrates (amylase)


 Lipase  digestion of fats
 IgA  mucous immunity -Bacteriostatic/bacteriocidal actions
 Lactoferrin  binds fe needed by bacteria –stops bacteria growth
 Lysozyme kills bacteria
 Facilitates speech
 Cleanse teeth
o Contains
 enzymes
 Amylase
 Salivary lipase
 IgA – will either kill bacteria or not allow it to grow
 Ions
 Potassium
 Sodium
 Bicarbonate
 Chloride
o Acinar cells- produce the enzymes, mucins, water and ions (also R protein)
o Ducts -may produce some fluid, but mainly responsible for modifying the
composition
o Stromal cells – produce antibodies, various bacteriostatic components
Potential problems with the oral cavity
o Mumps
 Viral infection
 Inflammation of parotids
o Xerostomia
 Reduced saliva output
 Causes difficulties in speech and swallowing
 Often associated with increased dental caries
o Inadequate saliva flow
 Lessens functions of taste buds
 Downstream effects on gastric and intestinal secretions/motility
 Combined with lowered amylase/lipase activity can reduce nutritive gain
from ingested foods
GI tube
o Contains 4 layers:
 Mucosa
 Epithelial lining
 Lamina propia of CT with blood and lymph vessels
 Muscularis mucoase
o Consists of a thin inner and outer layer of smooth muscle to
separate from submucosa
 Submucosa
 Function:
o Facilitates motility of mucosa
 Dense connective tissue with blood and lymph vessels
 Nerve plexus (Meissner’s)


 PARASYMPATHETICS ONLY
Muscularis externa
 Function:
o Control lumen size and motility of tube
 Smooth muscle cells spirally oriented
 2 categories:
o Internal sublayer (close to the lumen) circular
o Outer layer is longitudinal
 Myenteric nerve plexus is found in between the two muscular
layers (pre and post-ganglionic parasympathetic)
Serosa
 Loose connective tissue and adipose tissue with a mesothelium
o Esophagus




Mucosa
o A single longitudinal layer of smooth muscle
 Epithelium
o Stratified squamous nonkeratinized epithelium
 Lamina Propria
o Contains
 Mucous secreting esophageal cardiac glands
Submucosa
 Contains
o Mucous secreting esophageal glands proper
Muscularis externa
 Upper third: skeletal muscle
 Middle third: smooth and skeletal muscle
 Lower third: smooth muscle
 Contains the two sphincters for conveying food through tube
Adventitia – NOT SEROSA
o Stomach


Function:
 Acidifies and converts food into a thick, viscous fluid known as
chyme
 Produces digestive enzymes and hormones
Mucosa
o Poorly defined inner circular layer
o Outer longitudinal layer
o Contains mucinogen producing surface lining cells (these
are NOT goblet cells)
 Epithelium
o Simple columnar
o NO goblet cells
 Lamina Propria
o Loose CT
o Contains










Gastric glands
Smooth muscle cells
Lymphocytes
Plasma cells
Mast cells
Fibroblasts
Submucosa
 Dense, irregular collagenous CT
 Contains:
o Fibroblasts
o Mast cells
o Lymphoid elements
o Meissner (submucosal) plexus
o Arterial and veonous plexuses
Muscularis Externa
 Function:
o Mixes gastric contents
o Empties stomach
 3 layers of smooth muscle
o Incomplete inner oblique layers
o Thick middle circular layer (Forms the pyloric sphincter)
 Myenteric plexus in between these two layers!!
 Myenteric plexus is parasympathetic and
enteric innervations
o Innervates muscularis externa
o Outer longitudinal layer
Serosa
 There is one!
Structures associated with the stomach:
 Gastric glands (fundus)
o Parietal cells
 Secrete hydrochloric acid and gastric intrinsic
factor (binds b12, absorbed in the ileum)
 Lined by microvilli
 Increase surface area for absorption
 Contain intracellular canaliculi
 Location:
 Fundus of stomach
 Look like a fried egg!
o Chief cells
 Secrete pepsinogen (precursor of enzyme pepsin),
rennin, lipase
 Location:
 Fundus of stomach
o Mucous neck cells
 Located in neck of gland


Possess short microvilli, mucous granules at apex,
many mitochondria
 Function: make stem cells to replace mucosa
epithelium
o Enteroendocrine cells
 Includes many different cell types
 Each only secretes one hormone
 Table 15-1 in book
 Location:
 Islet of langerhans (pancreas), gastric pits
(stomach), intestines, colon
 Function:
 Secrete serotonin, CCK, somatostatin
Regulation of gastric secretion:
o Gastrin
 Produced by enteroendocrine cells
 STIMULATES HCl secretion
o Somatostatin
 Produced by enteroendocrine cells
 INHIBITS HCl secretion
o Small Intestines

Characteristics of all parts:
 Mucosa
o Inner circular layer of smooth muscle
o Outer longitudinal layer of smooth muscle
o Epithelium
 Simple columnar
 Contains
 Goblet cells
o Secrete mucin, a protective coating
of lumen
 Surface absorptive cells and
enteroendocrine cells
o Glycocalyx covering the microvilli
o Well developed tight junctions and
adhesive junctions
o Lamina propria
 Loose CT
 Contains
 Crypts of lieberkuhn
o Goblet cells
o Neuroendocrine cells
o Paneth cells
 Secrete lysozyme
 Stop bacteria growth in
crypts






o Regenerative cells
 Stem cells
Lymphoid cells
o Microfold cells
 Ileum in peyer’s patches
 Take antigens from
intestinal lumen to peyer’s
patches
o B lymphocytes
o Plasma cells
 Manufacture IgA
Fibroblasts
Nerve endings
Smooth muscle cells
Lacteals
o Lymphatic capillary
o Filters chyle
Capillary loops
o
Submucosa
o Consists:
 Lymphatic vessels
 Nerve fibers
 Meissner plexus
 ***Mucosa and submucosa form plicae/circular folds
 Muscularis Externa
o Two layers of smooth muscle
 Inner circular (ileocecal sphincter)
 Outer longitudinal
o Myenteric plexus is between the two layers of muscle
 Serosa
o Covers all of the jejunum, ileum and part of the duodenum
o Adventitia covers the remainder of the duodenum
Duodenum (unique characteristics)
 Submucosa
o Brunner glands
 Produce
 alkaline fluid – protects duodenal epithelium
from acidicchyme
 uragastrone – polypeptide hormone that
enhances epithelial cell division and inhibits
HCl production


o Large intestines

Function:
 Absorption of electrolytes, fluids, and gases.


Dead bacteria and food are compacted into feces
Produces mucus which lubricates lining and facilitates passage of
feces
o Cecum, colon

Mucosa
 2 layers of smooth muscle
o Inner circular
o Outer longitudinal
 Epithelium
o NO villi
o Simple columnar
o A LOT of goblet cells
o Surface absorptive cells
 Lamina propria
o Similar to small intestines
 Crypts of lieberkuhm WITHOUT panneth cells
 Submucosa
 Fibroelastic CT
 Contains
o Blood
o Lymphatic vessels
 Muscularis externa
 2 layers of smooth muscle:
o Inner circular
o Outer longitudinal
 Other layer forms teniae coli making haustra
coli
o Myenteric plexus is found between the two layers
 Serosa
 Adventitia covers the ascending and descending parts of the
colon
 Serosa covers the rest
o Rectum (similar to colon but fewer crypts of lieberkuhn)
o Anal Canal

Mucosa
 Two layers of smooth muscle that terminate at the valves:
o Inner circular
o Outer longitudinal
 Epithelium
o Simple columnar  simple cuboidal (closer to the anal
valves)
o Stratified squamous non-keratinized far from anal valves
o Stratified squamous keratinized at the anus
 Lamina propria
o Fibroelastic CT



o Contains
 Sebaceous glands
 Hair follicles
 Large veins
Submucosa
 Dense irregular CT with large veins
Muscularis externa
 Voluntary control
 2 layers of smooth muscle
o Inner circular (forms internal anal sphincter)
o Outer longitudinal
Adventitia attaches to anus
o Appendix


Mucosa
 Two layers of smooth muscle:
o Inner circular
o Outer longitudinal
 Epithelium
o Simple columnar
o Contains
 Columnar cells
 Goblet cells
 Lamina propria
o Many lymphoid nodules!!!
o NO villi
o Crypts of liberkuhn
o Paneth cells
 Submucosa
 Fibroelastic CT
 Lymphoid nodules
 Muscularis externa
 2 layers of muscle
o Inner circular
o Outer longitudinal
 Serosa
 Completely surrounds appendix
Digestion and absorption
o Carbs
 Salivary and pancreatic amylases
 Hydrolyze carbohydrates to disaccharides
 Begins in the oral cavity, continues in the stomach, completed in
the small intestine
 Disaccharidases
 Present in glycocalyx, cleaves disaccharides into monosaccharides
 Monosaccharides actively transported into surface absorptive cells
o Proteins (Pepsin  pancreatic proteases  dipeptides)
 Pepsin
 Lumen of the stomach partially hydrolyzes proteins into
polypeptides
 Pancreatic proteases
 In lumen of small intestines
 Hydrolyze the polypeptides from stomach into dipeptides
 Dipeptides
 Cleaved into amino acids in glycocalyx
 Transported into surface absorptive cells
 Discharged into lamina propria, where they enter circulation
o Fats
 Degraded by pancreatic lipase into monoglycerides, free fatty acids, and
glycerol in the lumen of the stomach
 Bile salts
 Act on free fatty acids and monoglycerides, forming watersoluble micelles
 Micelles
 And glycerol enter the surface absorptive cells
 Formation of chyle
 Triglycerides  chylomicrons – formed in golgi complex 
exocytosed into basal lamina, lacteals in lamina propria
create chyle
 Chyle enters submucosal lymphatic plexus
•
•
•
•
•
•
•
•
•
Give the location and function in the digestive tract of:
gastric pits  folds of lining epithelium.
• Location: mucosa in stomach
• Function: lead to gastric glands
Cardiac glands  secrete mucous
Pylorous glands  secretes mucous
• D cell: somatostatin  inhibits release of GI hormones
• G cell: secretes gastrin  increase motility, HCl/pepsinogen secretion
Villi
• Location: small intestines surface. Mucosa (not in large intestine)
• Function: principal site of absorption
Microvilli
• Function: increase surface area for absorption
Peyer’s patches –clusters of lymphatic nodules
• Location: ileum in lamina propria
• Function:Run immune response in mucosa
Parasympathetic neurons
• In the submucosa and muscularis externa
Enteric neurons
• Alimentary canal (smooth muscle)
• Function independently of CNS
•
•
•
•
•
Sympathetic axons
• Muscularis externa
Secretin
• Made in duodenum
• Secretes pancreatic enzymes and bicarbonate
Micelles
• Location: chyme
• Function: absorbed and convert to chylomicrons
Chylomicrons
• Location: lacteal in small intestines
• Function: form chyle
Zymogen granules
• Location: pancreas
• Function: inactive digestive enzyme precursor
Respiratory system
Conducting components:
Nasal/oral cavity  naso/oropharynx larynx trachea bronchi  bronchioles 
terminal bronchioles
Gas exchange components:
Respiratory bronchioles  alveolar ducts  alveolar sacs  alveoli

Nasal cavity
o Function:
 Lining is designed to do further removal of particles (conditioning)
o Olfactory epithelium
 Function:
 Conduction of smell to the brain
 Location: roof of nasal cavity, sides of nasal septum, and superior nasal
conchae
 Structure: pseudostratified columnar epithelium
 Highly modified cilia to be sensory cells
 Consists of
o Few goblet cells
o Olfactory cells and neurons
 Bipolar nerve cells
o Supporting sustenacular cells
 Many microvilli
o Basal cells
 Rest on basal lamina
 Regenerative
o Bowman glands
 Produce thin, watery secretion SEROUS
o Respiratory mucosa epithelium
 Function:
 Gas exchange (I don’t think so…I think probably conducting)



Location:
Structure:
 Pseudostratified ciliated columnar epithelium
 Thick basement membrane
 Contains goblet cells
 Basal cells
 Enteroendocrine cells (serotonin)
Conducting passageways
o Pharynx
o Larynx





Function:

Structure:
 Hyaline cartilage
o Thyroid, cricoids, and lower part of aretenyoids
 Elastic cartilage
o Epiglottis, corniculate
 Skeletal muscle
 Connective tissue
 Glands
Vocal cords
 Stratified squamous keratinized (?) epithelium
 Skeletal muscle
o Vocalis muscle
 Vocal ligament
**Inferior to the vocal cords, all goes to respiratory epithelium
False vocal cords (vocal folds)
 Loose connective tissue
 Contain
o Glands
o Lymphoid aggregations
o Fat cells
 Stratified squamous epithelium
 Mostly mucous, some serous
o Trachea


Function:
 Move inhaled particulate matter trapped in mucus toward the
oropharynx, to protect lung tissue from damage
Structure:
 Hyaline cartilage
 Fibro elastic CT
 Respiratory epithelium:
o Long, actively motile cilia
o Microvilli
o Mature goblet cells



o Enteroendocrine cells
o Short basal cells
Lamina propria – thin
Submucosa
o Contains seromucous glands
Ad ventitia
o Contains hyaline cartilage
o Bronchii


Function:
Structure:
 Respiratory epithelium
 Hyaline cartilage
 Spiraling smooth muscle bundles separate lamina propria from
submucosa, which contain seromucous glands
o Bronchioles (Primary)


Function:
Structure:
 Smooth muscle – no cartilage (helps with lab)
 Submucosa – NO glands
 Epithelium
o Ciliated columnar with goblet cells in larger airways
o Ciliated cuboidal with clara cells in smaller airways
o Divide into terminal bronchioles
o Terminal bronchioles


Function:
Structure:
 Epithelium
o Simple cuboidal
o Clara cells
 Divide and differentiate into ciliated cells
 Secrete glycosaminoglycans
 Metabolize airborne toxins, a process carried out by
cytochrome P-450
o Ciliated cells
o NO goblet cells
****Lung tissue  smaller bronchus
NO lung tissue  larger bronchus (lined by respiratory epithelium)
Changes from bigger to smaller passageways:
-
Epithelium gets thinner
Goblet cells disappear and then cilia cells disappear
Helpful hint:
Vessels carrying blood to the lung are next to the bronchioles
Vessels that drain the lung are far from the bronchioles
Bronchus  bronchiole terminal bronchiole  respiratory bronchiole  alveoli
 Respiratory pathways (Now begins to GAS EXCHANGE portion of the
respiratory system)
o Respiratory bronchiole

Structure
 Simple cuboidal epithelium
 Contains
o Clara cells
o Ciliated cells
o Alveoli



Function:
 Oxygen and carbon dioxide diffuse between air and blood
Structure
 Connective tissue with elastic (important for respiration) and
reticular fibers
 Simple squamous epithelium
 Contains
o Capillaries
o Macrophages – Dust cells
 Connective tissue  air space, scarf up debris but
don’t have the enzymes to degrade “dust cells”
o Alveolar cells
Alveolar cells
 Pneumocytes
o Type 1
 Most numerous
 Thin cytoplasm
 Tight junctions – prevent fluid from pasing
 Phagocytic abilities
 Not able to divide
 Function in gas permeability
 Not mitotic
o Type 2
 Larger
 Inside septum
 Mitotic
 Produce pulmonary surfactant via lamellar
bodies
 Phospholipids
 Proteins
 Surfactant is secreted but not cleared, coats
the cells
 Reduces the surface tension so that alveoli
stay open




Fat cells
Surfactant production and function: disease:
Know the diseases in slides!!! Write a little bit about it….
Hyaline membrane disease – infant respiratory distress syndrome
Insufficient surfactant production  terminal air spaces (future alveoli) collapse
Can treat with glucocorticoids or synthetic surfactant intratrachea
Surfactant production and function
o Source of surfactant: lamellar bodies in pneumocyte type 2
o Composition: dipalmitoylphosphatidylcholine
o Function: reduce surface tension, reduce effort to inflate alveoli
Blood-air barrier
o Structure:
 Thinnest regions
 Type 1 pneumocytes and layer of surfactant lining alveolar air
space
 Fused basal lamina of type 1 pneumocytes and capillary
endothelial cells
 Endothelium of the continuous capillaries within the interaveolar
septum
 Thickest regions
 Interstitial area interposed between two basal lamina which are not
fused
o Function:
 Permits diffusion of gases between alveolar airspace and blood
Male Reproductive system
 Organs of the male reproductive system
o Testes
o Genital ducts
o Accessory genital glands
 Seminal vesicles
 Prostate gland
 Bulbourethral gland
o Penis
 Overall function:
o Production of spermatozoa, testosterone and seminal fluid
 Testes
o Structure:
 Epithelial tube:
 Creates a blood-testes barrier
 Puts a barrier between immune system and antigens
 Tunica Vaginalis
 Serous sac derived from peritoneum that partially covers anterior
and lateral surfaces of each testes
 Tunica Albuginea
 Thick, fibrous dense CT capsule of testis
 Lined by vascular layer of CT, tunica vasculosa
 Mediastinum testis
 A posterior thickening which is an incomplete CT septa to divide
the organ into different compartments (250 lobuli testes)
o Interstitial (Leydig) cells – endocrine cells
 Within the lobuli testes but not within each seminniferous tubule
 Structure:
 Large central nucleus
 Many mitochondria
 Well-developed golgi complex
 Many lipid droplets
o Contain cholesterol esters  precursor to testosterone
 Capillaries
 Function:
 Endocrine cells that produce and secrete testosterone
o Stimulated by luteinizing hormone (produced in the
pituitary gland)
o Important for maturation of spermatazoa
o These cells mature during puberty in males
o Seminiferous tubules
 Structure
 Enveloped by fibrous CT tunic with many fibroblasts and
capillaries
 Straight tubules connect with the Rete Testes
o Straight tubules are composed only of Sertoli cells
o Take away spermatagonia and progeny cells
o Simple cuboidal with microvilli and a single flagella
 Lined by thick complex epithelium containing:
o 4-8 layes
o Spermatagenic cells
o Sertoli cells
 Structure:
 Pale, oval nucleus, large nucleolus
 Receptors for follicle-stimulating hormone
(FSH)
 Form tight junctions with adjacent sertoli
cells
o These are responsible for the bloodtestes barrier
 Protects developing sperm
from autoimmune reactions
 Function:
 Support, protect, and nourish the
spermatogenic cells
 Phagocytose excess cytoplasm discarded by
maturing spermatids
 Secrete a fructose-rich fluid into lumen
which aids transport of spermatozoa
 Synthesize androgen-binding protein
(stimulated by FSH) and inhibin
o ABP -Assists in maintaining the
necessary concentration of
testosterone in seminiferous tubule
lumen so that spermatogenesis can
occur
o Inhibin – inhibits FSH in feedback
loop
o Spermatogenesis
 Process of spermatozoa formation. 3 phases
 Spermatocytogenesis – differentiation of
spermatagonia into primary spermatocytes
 Meiosis – reduction division to reduce
diploid chromosomal complement of
primary spermatoctes to from haploid
spermatids
 Spermiogenesis – transformation of
spermatids into spermatozoa
 During spermatogenesis, daughter cells remain
connected to eachother via intercellular bridges
o Spermatogenic cells
 Spermatagonia
 1. Replace themselves
 2. Differentiate into sperm
 Diploid germ cells adjacent to the basal
lamina of the seminiferous epithelium
 At puberty, testosterone influences them to
enter the cell cycle
o Type A
 Light – mitotically active
 Dark – mitoticall inactive
o Type B
 Undergo mitosis and give rise
to primary spermatocytes
 Spermatocytes
 Primary spermatocytes
o Large diploid cells with 4CDNA
content
o Undergo 1st meitotic division to form
secondary spermatocytes
 Secondary spermatocytes
o Haploid cells with 2CDNA
o Quickly undergo 2nd meitotic
division to form spermatids
 Spermatids
 Haploid cells with only 1CDNA
 Located near the lumen of seminiferous
tubule
 Nuclei with condensed chromatin
o Spermiogenesis
 Unique process of cytodifferentiation where
spermatids get rid of their cytoplasm and transform
into spermatozoa
 4 phases
 Golgi phase
o Form acrosomal granule and
acrosomoal venule
o Get flagella
 Cap phase



 Genital ducts
o Expansion of acrosomal vesicle
forming the acrosomal cap
 Later chews away the oocyte
using hydrolytic enzymes
Acrosomal phase
o Nucleus is condensed
o Spermatid elongates
Maturation phase
o Loss of excess cytoplasm and
intercellular bridges
o Spermatozoa are immotile until
they leave the epididymis
o They become able to fertilize in the
female reproductive system
Spermatazoa can be stored in the tail of
epididymis or in the beginning of the vas
deferens
o Intratesticular ducts
 Straight tubules  rete testis
o Extratesticular ducts
 Efferent ducts
 Lead from rete testis  epididymis
 Contain
o Smooth muscle
o Simple epithelium with nonciliated cuboidal cells and
ciliated columnar cells
 Function: reabsorb fluid from semen
o Conduct sperm from rete testes to epididymis
 Ductus epididymis
 Ductus epididymis + efferent ducts = epididymis
 Structure:
o Circular layers of smooth muscle that undergo peristaltic
contractions, which help convey sperm  vas deferens
o Lined by pseudostratified columnar epithelium with 2 types
of cells
 Basal cells – precursors to principal cells
 Principal cells – columnar with nonmotile sterocilia
on luminal surfaces
 Function:
o Fluid resorption
o Secrete glycerophosphocholine
which inhibits fertilization
o Function:
 Conduct sperm from efferent ducts to vas deferens
 Vas Deferens


Structure:
o Thick muscular wall with inner and outer layers of
longitudinal smooth muscle
 Separated by a layer of circular smooth muscle
o Irregular lumen lined by pseudostratified columnar
epithelium
 Function:
o Deliver sperm from tail of epididymis to ejaculatory duct
Ejaculatory duct
 Structure:
o Lacks a muscular wall
o Straight continuation of vas deferens beyond where it
receives the duct of the seminal vesicle
o Enters prostate gland and terminates in the colliculus
seminalis in the prostatic urethra
 Function
o Deliver sperm, seminal fluid to prostatic urethra at
colliculus seminalis
 Accessory genital glands
o Seminal vesicles


Structure:
 Epithelium
o Pseudostratified columnar
o Height varies with testosterone levels
o Contains yellow lipochrome pigment granules, secretory
granules, golgi, mitochondria and abundant RER
 Lamina Propria
o Fibroelastic CT
o Inner circular layer of smooth muscle
o Outer longitudinal layer of smooth muscle
 Adventitia
o Fibroelastic CT
Function:
 Secrete yellow, viscous fluid (seminal fluid) that activates sperm
(fructose). The majority of the ejaculate
 Seminal fluid is not in contact with sperm until ejaculation
o Prostate gland

Structure:
 Convered by fibroelastic capsule with smooth muscle
 Surrounds urethra as it exits urinary bladder
 Has branched tubuloalveolar glands, which empty contents into
prostatic urethra
o Glands arranged in 3 layers surrounding urethra
 Mucosal
 Submucosal

 Main
 Epithelium:
o Simple or pseudostratified columnar
o Contains
 Many RER
 Golgi
 Many lysosomes
 Secretory granules
 Prostatic concretions – corpora amylacea** Pic test Q
o Composed of glycoprotein, which becomes calcified
o No real purpose
Function:
 Secretes a whitish fluid
 Synthesis is regulated by dihydrotestosterone
o Bulbourethral gland


Structure:
 Adjacent to membranous urethra
 Simple cuboidal or columnar epithelium
 Surrounded by fibroelastic capsule with smooth and skeletal
muscle
Function:
 Empty secretion into lumen of membranous urethra to lubricate it
Component
Origin
contents and function
secretions of seminal
vesicles
seminal vesicles
Fructose; nutrients for sperm
prostate gland
bulbourethral gland
seminiferous tubules
Citric acid; nutrients for sperm
Alkaline secretion; neutralize acidic
environment in vagina
Acid phosphatase, PSA
mucous; lubrication of urethra
sperm; fertilizes egg
prostatic secretion
bulbourethral secretion
spermatazoa

Spermatic cord
o Function:
 Conveys spermatozoa from the epididymis to the prostate gland
o Structure:
 3 layers of smooth muscle
 Also contains the cremaster muscle (skeletal muscle)
 Penis
o Corpus cavernosum
 Structure:


Paired masses of erectile tissue with irregular vascular spaces lined
with continuous layer of endothelial cells
 Separated from one another by trabecular of CT
 Very vascular
Function:
 During erection, vascular spaces become engorged with blood as a
result of parasympathetic impulses
o Increases blood flow to vascular spaces to copus
cavernosum and spongiosum
o Corpus spongiosum

Structure:
 Single mass of erectile tissue that contains vascular spaces of
uniform size
 Trabeculae has more elastic fibers and less smooth muscle than CC
o Tunica Albuginea



Shows stripes in the pictures
Thick, fibrous, connective sheath that surrounds both corpus cavernosum
and the corpus spongiosum.
Permits extension during erection
o Glans penis



Dilated distal end of corpus spongiosum
Dense CT and longitudinal muscle fibers
Covered by prepuce, stratified squamous keratinized epithelium
Sperm pathway
Seminiferous tubules  tubuli recti  rete testis  efferent ductules  epididymis  vas
deferens  ejaculatory duct  prostatic urethra  membranous urethra  cavernous/penile
urethra
Endocrine Glands

Endocrine cells
o Secrete inward, across basement membrane
o Most hormones act at a distance from the site of secretion
 Act on target tissues or target organs
o Interact closely with the nervous system and the immune system
 Pituitary gland/hypohphysis
o Lies in the sphenoid bone/sell turcica
o Receive blood from the internal carotid artery via fenestrated capillaries
o Hypophyseal portal system carries it away
 Portal system provides a link between the hypothalamus and the pituitary
gland
o 2 glands within:
 Neurohypophysis (posterior part)
 From neural origin
 Neural secretory tissue


Function:
o Regulation of adenohypophysis function through releasing
hormones
o Synthesis and secretion of oxytocin and ADH
 Consists of:
o Pars nervosa
 Does not contain cells that secrete!
 THE AXONS DO SECRETE (they are in the
hypoth+alamus) -Contains unmyelinated axons of
secretory neurons situated in supraoptic and
paraventricular nuclei
 Secretory neurons contain nissl bodies
 Form Herring bodies
 Neurosecretory contains two hormones
(regulated by the hypothalamus):
o Arginine vasopressin (antidiuretic
hormone ADH)
 Supraoptic nuclei produce
 Regulate osmotic balance
o Oxytocin
 Paraventricular nuclei
produce
 Stimulates contraction of
myoepithelial cells that
surround the ducts of the
mammary glands
 Pathway: hypothalamus
secretes oxytocin axon
pars nervosa mammary
gland or uterus
o Infundibulum
 Neurosecretory axons make
hypothalamohypophysial tracts
o Neural stalk
 Composed of:
 Stem
 Median eminence
Adenohypohpysis (anterior part)
 From epithelial origin – Rathke’s pouch/oropharynx
 Glandular epithelial tissue
 Consists of:
o Pars distalis (anterior lobe)
 Organized in chords
 3 cell types:
 Chromophobes
o With granules

o Without granules
 Chromophils: (parenchymal cells)
o Basophils
o Acidophils
 5 types of hormone secreting cells:
 Somatotropic cell
o Growth hormone (GH, somatotropin)
o Acidophilic
 Mammotropic
o Prolactin (PRL)
o Acidophilic
 Gondaotropic
o Follicle stimulating hormone
o Leutinizing hormone
o Basophilic
 Thyrotropic cell
o Thyrotropin (TSH)
o Basophilic
 Corticotropic cell
o Corticotrophin (ACTH)
o Basophilic
All hormones below require the release of hypothalamic releasing
hormone in order to release their product
Secretory cell
Hormone
Stain Reacti
Somatotrope
Growth H (Somatotropin)
Acidophil
Mammotrope
Prolactin
Acidophil
Gonadotrope
Follicle Stimulating H
Basophil
Gonadotrope
Luteinizing H
Basophil
Corticotrope
Adrenocorticotropic H
Basophil
Thyrotrope
Thyroid-Stimulating H
Basophil
o Pars tuberalis (cranial part)
 Surrounds neural stalk
 Most of the cells secrete gonadotropins-follicle
stimulating hormone and luteinizing hormone
o Pars intermedia
 Develops from dorsal part of Rathke’s pouch

Produces melanocyte-stimulating hormone
o Hypothalamo-hypophyseal portal system
 Hypophysis is connected to the hypothalamus
 3 known sites of production of hormones that give off 3 groups of
hormones:
 Secretion: Peptide
o Produced by: aggregates (nuclei) of secretory neurons in
the hypothalamus: the supraoptic and the paraventricular
nuclei
 Secretion: peptide hormones

o Produced by:neurons of the dorsal medial, ventral medial,
and infundibular nuclei of the hypothalamus
 Secretion: proteins and glycoproteins
o Produced by: cells of the pars distalis
Via the portal system, blood can go from pars distalis  pars nervosa 
hypothalamus
 Hormones can directly feedback hypothalamus without going
through entire system
 Pineal gland
o Structure:
 Projects from roof of diencephalon (3rd ventricle of brain)
 Capsule formed of pia mater
 Contains calcified concretions (brain sand) in intersititium – function
unknown
 Composed primarily of pinealocytes and neuroglial cells
 Pinealocytes – chief cells of gland
o Most abundant
o Arranged in cords
o Main secretory cells
 Secrete melatonin (during night) upon sympathetic
stimulation from cranial cervical ganglion
 Regulates reproduction and sexual
behavior
 Decreases production of gonadal steroids
 Also secrete serotonin (during day)
o Contain
 Secretory granules
 Microtubules
 Microfilaments
 Synaptic ribbons
 Lipid droplets
 Large nucleus with one or more prominent
nucleoli
 Neuroglial cells – interstitial cells
o Similar to astrocytes
o Contain microtubules, microfilaments, and intermediate
filaments
o Function:
 Effects circadian rhythms, sexual behavior, and reproduction
 Thyroid gland
o Thyroid follicles
 Structure
 Filled with colloid ( iodinated thyroidglobulin)
 Produced by follicular lining cells

Enveloped in a layer of epithelial cells, called follicular cells,
which are surrounded by parafollicular cells
 Fenestrated capillaries present
 Function:
 Synthesize and store thyroid hormones
o Follicular cells
 Structure
 Normally cuboidal, columnar when stimulated, and squamous
when inactive
 Contain
o RER with many ribosome free regions
o Golgi supranuclear
o Many lysosomes
o Rod-shaped mitochondria
o Small apical vesicles
 Involved in transport and release of thyroglobulin
and enzymes into the colloid
o microvilli
 function
 synthesis and release of thyroid horomes thyroxine (T4) and
triiodothyronine (T3)
o processes promoted by TSH, which binds to G-proteinlinked receptors on the basal surface of follicular cells
o Parafollicular cells (C cells) clear cells
 Structure:
 Stain less intensely than follicular cells; pale
 In the basal lamina, no contact with lumen
 Present singly or in small clusters
 Belong to DNES population, enteroendocrine cells
 Contain
o Elongated mitochondria
o Many RER
o Golgi
o Secretory granules (membrane bound)
 Function:
 Synthesize calcitonin
o Polypeptide hormone, in response to high blood calcium
levels
 Drives calcium/serum levels DOWN
o Target organs are bone, kidney
 Parathyroid gland
o Structure:
 4 small glands that lie on posterior surface of thyroid gland, embedded in
CT capsule
 1 embedded in each thyroid lobe
 1 external beside each thyroid lobe
 Contain fat cells
 Parenchyma composed of two cell types:
 Principal (Chief) cells
o Small basophilic cells arranged in clusters
o Anastomosing cords with fenestrated capillaries surround
o Contain
 Central nucleus
 Golgi (Well developed)
 Many RER
 Small mitochondria
 Glycogen
 Secretory granules
o Function:
 Secrete parathyroid hormone (PTH)
 INCREASES serum calcium levels
 High blood calcium levels inhibit production of
PTH
 Stimulates osteoclast to break down bone so there is
more calcium in the blood. Also tell kidney to retain
calcium and secrete phosphatase
 Oxyphils
o Large acidophilic cells
o Present singly or in small clusters within the parenchyma of
the gland
o Contains
 Many, large mitochondria
 Poor golgi
 Not many RER
o Function: unknown
o Function:
 Adrenal gland
o Structure
 Lie embedded in fat above kidney
 Cortex
 Structure
o Derived from mesoderm
o 3 separate regions
 Zona glomerulosa
 Structure
o Small cells in archlike cords and
clusters
o Small lipid droplets
o Many SER
o Shelf-like cristae in mitochondria
 Function

o Synthesize and secrete
mineralcorticoids (mostly
aldosterone).
 Regulate electrolyte, water
balance via effect on cells of
renal tubules
 Raise blood volume and BP
o Hormone production stimulated by
angiotensin 2 and ACTH
Zona fasciculate
 Structure
o Columns of cells
o Sinusoidal capillaries
o Contain many lipid droplets so they
are called spongiocytes
o Spherical mitochondria with tubular
and vesicular cristae, and lipofuscin
pigment granules
o Large cells, stain poorly (lipid
droplets)
 Function
o Synthesize and secrete
glucocorticoids (mostly cortisol
and corticosterone)
 Regulate carb metabolism by
promoting gluconeogenesis;
promote breakdown of
proteins, fat
 Anti-inflammatory properties
 Suppress immune response
 Facilitate maturation of fetus
 Increase glomular filtration
and free water clearance
 Maintain muscle function,
decrease muscle mass
 Decrease bone formation,
increase bone resoprtion,
decrease CT
 Maintain cardiac output,
increase arteriolar tone,
decrease endothelial
permeability
o Hormone production is stimulated
by ACTH – corticotrophs in
pituitary gland  has the most
effect here in fasciculada



Zona reticularis
 Structure
o Cells arranged in anastomosing cords
o Man large lipofuscin pigment
granules
 Function
o Synthesizes and secretes weak
androgens
(dehydroepiandreosterone and
androstenedione)
 Promote masculine
characteristics
o Hormone production stimulated by
ACTH
Function
o Synthesize and secrete, DO NOT STORE steroid
hormones
Medulla
 Derived from ectodermal neural crest
 Basically, a completely different gland from the cortex
 Structure
o Invested by cortex
o 2 populations of parenchymal cells
 Chromaffin cells
 Structure:
o Large, polyhedral cells with
secretory granules that stain with
chromium salts
o Arranged in short, irregular cords
surrounded by capillaries
o Innervated by preganglionic
sympathetic (cholinergic) fibers
o Contain
 Golgi
 RER
 Many mitochondria
 Membrane bound granules
containing catecholamines,
ATP, enkephalins, and
chromogranins – help for
binding norepinephrine and
epinephrine
 Function:
o Synthesize, STORE, and secrete
catecholamines (a modified amino
acid) – epinephrine and
norepinephrine
o Release occurs in response to intense
emotional stimuli
o Mediated by preganglionic
sympathetic fibers
o Epinephrine – flight or fight
response; increases heart rate, force
of contraction; relaxes bronchiolar
smooth muscle; promotes
glycogenolysis, lipolysis
o Norepinephrine – little effect on
cardiac output, rarely used clinically
o norepinephrine is initially created,
stored in vesicles and made into 
epinephrine
Sympathetic ganglion cells


Endocrine portion of the pancreas
o Islets of langerhans
 Structure
 Richly vascularized spherical clusters
 Surrounded by reticular fibers
o Islet cells
 Can’t really be distinguished without
immunocytochemistry
 Produce seceral polypeptide hormones, but each
cell type only produces ONE hormone
 Islet hormones produced
Panc. Islet cell
Alpha cells
Beta cells
Delta cells
F cells
G cells
hormone
Glucagon
insulin
function
increase serum glucose in blood
decrease serum glucose in blood
somatostatin
inhibits release of hormones by nearby
secretory cells and reduces motility of GI tract
and gall bladder by decreasing contraction of
smooth muscle
Pancreatic Polypeptide
Gastrin
inhibits release of exocrine pancreatic
secretions, stimulates gastric secretion, inhibits
intestinal mobility
stimulates gastric HCl secretion
Other secondary endocrine organs:
Pancreas – islet of langerhans (insulin, glucagon)
Stomach – mucosal enteroendocrine cells
Intestine – mucosal enteroendocrine cells
Kidney – interstitial cells (erythropoietin)
Heart – atrial myocardial cells (ANP)
Ovary – granulose and theca cells
Testis – sertoli cells and leydig cells
Placenta – trophoblast cells
Adipose tissue - leptin