Biology 2401 - Anatomy and Physiology I
Exam 1 notes - Introduction, Cell and Tissue Structure
Two major principles in study of animals bodies: (humans, like other living organisms
are product of evolutionary / adaptive process):
Structure is related to function - what a part does is affected by what it does.
anatomy = study of structure, physiology = study of function
1.2
Living bodies maintain homeostasis. Homeostasis = internal conditions of body
within narrow limits. Maintained by physiological mechanisms.
1.5
receptor ---------------> control center --------------> effector (muscle, gland, etc.)
stimulus (stress, change in conditions) ---------------> response (action of body)
feedback = response of body to stimulus.
negative feedback = response is opposite to changing condition, reverses change.
positive feedback = response is same as changing condition, increases change.
“long term” homeostasis - cells respond to stimulus over a time period (ex.
muscle atrophy or hypertrophy)
*How can disease be defined in terms of homeostasis?
*Which type feedback (negative or positive) is most important in maintaining
homeostasis?
Levels of organization in living organisms:
1.3
ecosystem
At what level is homeostasis maintained?
community
population
What are emergent properties? give some
individual organism
examples.
organ system
organ
tissue
cell
cell organelle
molecule
What is a very important emergent
atom
property at the cell level?
*
*
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Cells
Ch. 3
Cell theory - all living organisms made of cells
- cells are the basic unit of life (how does this relate to emergent properties?)
- cells come from living cells (no spontaneous generation under conditions on
earth today)
Cells small ( 5 um - 10 nm) . Why? What feature determines that active cells can not be
very large?
Surface area / volume ratio decreases as the cell becomes larger (less surface area
compared to its volume).
Cells have common structures, become different by exaggeration of some part.
Common cell structures and their function:
cell membrane - regulates what enters and leaves the cell
3.2, Table 3.1
cytoplasm (cytosol) - liquid medium in cell, many molecules dissolved and move
in cytoplasm
nucleus - houses and protects chromosomes
endoplasmic reticulum - internal membrane that partitions cytoplasm
Golgi apparatus - membrane layers that packages secretions
lysosomes - membrane sacs that contain digestive enzymes
ribosomes - assemble proteins
cytoskeleton - filaments and tubules that provide support and produce movement
mitochondria - provide most of energy for cell by “burning” fuel
Movement across cell membrane:
3.3 , Table 3.2
permeability = ability of materials to pass through
passive movement - no cell energy required
diffusion osmosis filtration
facilitated diffusion active movement - cell must expend energy to make this happen
active transport (ion pumps) vesicular transport - endocytosis (pinocytosis, phagocytosis,
receptor-mediated endocytosis)
- exocytosis
Tissues
Ch. 5
tissue = group of specialized cells and cell products that perform specialized function
intracellular = inside cell
intercellular (interstitial) = outside of cell, between cells
extracellular = outside cell, anywhere in body
cell connections attach cells - gap junctions, tight junctions, anchoring junctions
four major, or primary, tissue types: epithelial, connective, muscle and neural. 5.1
I. Epithelial tissues: surface covering tissue, many places in the body; glandular 5.2
protection from abrasion, drying, chemicals, bacteria
producing specialized secretions
controlling absorption and excretion of certain materials
sensory cells located in some epithelial tissues
lack blood vessels (avascular), and many lack nerves
cells close together with little intercellular space
cells can divide to produce new cells (stem cells)
many have specialized cell extensions (cilia, microvilli)
attached to deeper layers by basement membrane
Classification based on shape of surface cells (squamous, cuboidal, columnar) and the
number of layers of cells (simple or stratified)
Types of epithelial tissues in the body: (know these types, their features and where they
are located)
simple squamous simple cuboidal simple columnar pseudostratified columnarstratified squamous (keratinized and unkeratinized) stratified cuboidal transitional *What does “selectively permeable” mean? What is a concentration gradient?
*Glands are formed from epithelial cells. Distinguish between endocrine and exocrine
glands.
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Membranes = surface covering of cavities, usually secrete fluid
5.4
mucous membrane - line cavities that open to the exterior of body; secrete mucus
to prevent drying, protect surface
serous membrane - line cavities that are sealed and cover organ within the cavity;
secrete watery slick lubricant to prevent friction, have visceral and parietal
layers
synovial membrane - line joint capsules, secrete slick fluid to prevent friction
II. Connective tissues: deeper tissues of body that:
5.3
support and protect body and attach body structures (bone, cartilage, fibrous)
transport material throughout body (blood)
store energy (adipose)
defend body from foreign invaders (white blood cells)
cells in tissue not tightly connected, much intercellular space
intercellular space filled with ground substance (fluid) and protein fibers = matrix
ground substance composed of fluid, gel, crystalline
protein fibers are collagen, elastic, reticular
typical cells are fibroblast (“fiber makers”)
well vascularized and innervated (has blood vessels and nerves)
cells can reproduce
Types of connective tissues: (know the important features and the location of these)
connective tissues proper (may contain fibroblast, adipocytes and mast cells)
loose connective tissue - watery ground substance; scattered randomly
arranged fibers; anchors with flexibility
adipose tissue - loose connective with more adipocytes; insulates and
cushions, stores energy in the form of fat
dense connective tissue (fibrous tissue) - intercellular space mostly filled
with collagen fibers, little ground substance
irregular dense con. - fibers arranged in several directions; dermis
of skin
regular dense con. - fibers arranged in one direction, parallel;
tendons and ligaments
reticular connective tissue - three dimensional framework of reticular
fibers that forms “skeleton” of many organs
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supporting connective tissues (denser tissues with gel or crystalline ground
substance)
cartilage - ground substance firm gel; specialized type fibrocyte called
chondrocytes; avascular and noninnervated
hyaline cartilage - “glassy”; few collagen fibers; covers bones in
joints, rings in trachea, connects ribs
elastic cartilage - contains elastic fibers, flexible and retains shape;
external ear, nose
fibrocartilage - many collagen fibers; very tough, good support;
intervertebral disks in spine, between bones of pelvis, pads
in some joints
bone - calcium salts (crystalline) with callagen fibers; specialized
fibrocytes called osteocytes; rigid support
fluid connective tissues (watery ground substance, less fiber structure)
blood - contains red blood cells, white blood cells, platelets in a very fluid
matrix called plasma; transports materials throughout body
III. Muscle tissue: (more on these in muscular system)
very specialized to produce movement, maintain posture;
muscle cells contain large number of contractile proteins;
can not reproduce
three types of muscle - skeletal, cardiac and smooth
5.5
IV. Neural tissue: (more on these in nervous system)
5.6
very specialized to communicate, detect stimuli;
composed of neurons (communicating cells that can not reproduce) and neuroglia
(supporting cells)
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Skin and the Integumentary System
Ch 6
Skin (cutaneous membrane) is principle organ, plus accessory organs (hairs, glands, nails)
form integumentary system
Functions: protection from abrasion, drying, radiation, infection
regulation of body temperature (*Describe two ways)
houses some sensory organs
energy storage
excretion
synthesis of some important biomolecules
Skin composed of two layers and underlying layer that attaches to deeper body: 6.2
1. epidermis - top layer that is exposed at surface
- formed of stratified squamous epithelium
- important cell types are keratinocytes (keratin producing cells) and
melanocytes (melanin producing cells)
- distinct layers develop as cells divide and are pushed to the surface;
as cells push to the surface they produce keratin, die and flatten.
This forms dead tough protective layer at surface
- layers are called strata: stratum basale (bottom actively dividing
layer produces new cells), stratum spinosum, stratum granulosum
(producing keratin), stratum lucidum (only in thick skin where
callus is formed), stratum corneum (dead flat cells filled with keratin)
- melanocytes in stratum basale produce melanin, a pigment the
absorbs ultraviolet radiation
- pressure at surface and damage to cells stimulate growth of keratinocytes
- UV radiation stimulates melanocyte production of melanin
* Describe the growth pattern of the epidermis and explain why this pattern is important
in maintaining homeostasis.
* Describe two ways that the epidermis protects the body.
* What specific type tissue forms the epidermis?
2. dermis - composed mostly of irregular dense connective tissue
- provides mechanical strength of skin to prevent puncture and tearing
- composed of fibroblasts which produce much collagen and some elastic fibers
- good blood supply and nerves
- ridges of dermis (dermal papillae) form irregular surface with epidermis; this
increases surface for nutrient and waste exchange, sensory structures
* What specific tissue forms the dermis?
* What are dermal papillae and how do they help maintain the epidermis?
* What type fibers predominate in the dermis and how does the arrangement of these
fibers give strength to the dermis?
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3. subcutaneous - composed of lose connective tissue with some adipose tissue
- anchors skin to deeper layers but allows some movement
- some collagen with much fluid-filled space; larger blood vessels and nerves run
through spaces
- adipose cells also located in spaces; insulate to retain body heat, store energy,
form and cushion body surface
* Describe two ways that the integumentary system maintains body temperature.
6.3
Accessory structures (organs) in skin have various functions, all form from embryonic
stratum basale that is located in dermis or subcutaneous
1. nails - specialized keratinocytes that produce dense keratin
- strengthen and protect tips of fingers and toes
- nail plate grows from groove over nail bed
2. hairs - from specialized keratinocytes at base of hair follicle (hair root)
- melanocytes produce melanin in varying amounts, color hair
- shape of follicle determines shape of hair (straight, wavy, curly)
- structures associated with hair follicles:
arrector pili muscle - a small smooth muscle that pulls hair up to
“fluff” fur, causes goose bump
sebaceous gland - produces oil to lubricate and protect skin
apocrine sweat gland (in certain areas) - to produce body scent
root hair plexus - hair movement stimulates for very sensitive
3. glands - all skin glands are exocrine glands. What does this mean?
- sebaceous glands - produce oily substance (sebum) into hair follicle
to lubricate, waterproof skin and kill bacteria
- eccrine sweat glands (sudoriferous glands) - empty onto skin surface;
produce thin watery fluid to cool body
- apocrine sweat glands - produce viscous fluid that vaporizes to produce
body scent; into hair follicles of axillary, pubic and areola; active at
puberty
- mammary glands - produce milk in females to nourish young
- ceruminous glands - produce earwax in external ear canal to clean debris
from canal
* What is the origin, in the embryo, of the cells that develop into the accessory organs?
* List five types of glands in the skin and give their primary function.
* List four structures associated with hair follicles and give the function of each.
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