Integumentary System
 largest body system
 Consist of: skin (or integument) and its appendages
(hair, nails and certain glands)
Functions:
- protection of inner body structures
- sensory perception
- regulation of body temperature
- excretion of some body fluids
- synthesis of vitamin D
Skin (cutaneous membrane)
a. Skin
b. Skin Derivatives
- Sweat Glands
- Oil Glands
- Hairs
- Nails
Skin and Body Membranes
Skin:
• largest body organ
• weighs up to 5 kg, covers an area of 2 square meter
• forms the boundary between the body’s interior and its
surrounding
• contain sensory receptors
Function:
• Protection
• Sensory perception
• Body temperature regulation (thermoregulation)
• Excretion
• Synthesis
Functions:
Protection:
- protect deeper tissues against chemical and thermal
damage
- prevent invasion of skin from harmful microorganisms
- against UV rays of sun & desiccation (drying)
- maintain integrity of body surface by migration & shedding
- repair surface wounds thru cell replacement mechanism
Sensory Perception:
- sensory nerve fibers supply sensation to the skin
Body Temperature Regulation:
- nerves, blood vessels & eccrine glands within the skin’s
deeper layer (dermis) help control body temperature
(thermoregulation)
Excretion:
-sweat glands in the skin excrete sweat which contain water,
electrolytes, urea and lactic acid
Synthesis:
- vitamin D ( needed for bone metabolism)
Skin Structure
Epidermis
- outermost layer
- thickness varies
- no blood vessels
stratified squamous epithelium
- often keratinized (hardened by keratin)
Layers/ Stratum:
- S. corneum (horny layer): outermost layer;
keratinized
- S. lucidum (clear layer): blocks water penetration &
water loss
- absent in thin skin (occurs only in thick skin)
- S. granulosum (granular layer): responsible for
keratin formation
- may be missing in some thin skin
- S. Spinosum (spiny layer): helps in keratin formation;
rich in RNA
- S. Basale (basal layer): innermost; produce new cells
Dermis
- also called corium
- form the 2nd layer of skin
- elastic system: contain blood and lymphatic vessels,
nerves & epidermal appendages
2 Layers/ Stratum:
1. Papillary layer
- contain projections called dermal papillae
- contain pain receptors and capillary loops
2. Reticular layer
- made of collagen which provide strength, structure &
elasticity to skin
- contain blood vessels, gland and nerve receptors
Hypodermis or subcutaneous tissue
- layer of fat located deep to the dermis
• not part of the skin
• anchors skin to underlying organs
• composed mostly of adipose tissue filled
with fats
• Function: insulation, shock absorption,
storage of energy reserves
Fingerprints
• produced from fingerlike projections of papillary layer
of dermis which form ridges on fingers
• arise from interaction between individual’s genes &
developmental environment in the uterus
• genes determine general characteristics of fingerprint
patterns
Classification: whirl, arch, loop
WHIRL
ARCH
LOOP
Body Membranes
Membrane:
- thin sheet of material forming a barrier or lining
Function of body membranes
• Cover (or line)
• Protect
body surfaces
• Lubricate
Body Membranes has 2 major groups:
1. Epithelial Membrane
a. Cutaneous Membranes – Skin
b. Mucous Membranes – Open Body Cavities
c. Serous Membranes – Closed Body Cavities
2. Connective Tissue Membrane
a. Synovial Membrane – Joint Spaces
Epithelial Membrane
Cutaneous Membrane
 made up of skin
 exposed to air = dry membrane
 provide outermost protective boundary to the
body
Mucous Membrane
 cover all body cavities that open to exterior
surface
 adapted for absorption / secretion
 respiratory, digestive, urinary, reproductive
Serous Membrane
 cover body cavities that are closed to the exterior of
the body
 occur in pairs, producing 2 layers
- Parietal layer: forms outer
wall
- Visceral layer: forms inner
wall
Specific name depends on location:
 Peritoneum – abdominal
cavity
 Pleura – around lungs
 Pericardium – around heart
Connective Tissue Membrane
Synovial Membrane
• no epithelial cells
• lines fibrous capsules
surrounding joints
providing smooth
surface
• synovial fluidlubricant
What determines Skin Color
Melanin
• Yellow, brown or black
pigments
Carotene
• Orange-yellow pigment from some vegetables
Hemoglobin
• Red coloring from blood cells in dermis capillaries
• Oxygen content determines the extent of red coloring
Melanin
•
•
•
•
•
pigment produced by melanocytes
melanocytes - mostly found in stratum basale
color - yellow to brown to black
helps filter UV light/radiation
amount of melanin produced depends on:
-
genetic
sunlight exposure = stimulate melanin
production
Appendages
Sebaceous (oil) glands
- (+) all over skin except palms & soles
• produce oil (sebum)
- lubricant: makes skin soft & moist; hair- soft
- kills bacteria
• most have ducts that empty into hair follicles
• activated at puberty w/c makes skin oilier
• testosterone increases the activity of
sebaceous glands during puberty
SWEAT GLANDS (sudoriferous gland)
- widely distributed in skin
Two types
1. Eccrine sweat gland - ducts opens skin surface
- efficient in heat regulation
- nerve endings cause glands to secrete
sweat when external or body temperature is
high
- acidic pH (4-6) of sweat inhibit bacterial growth
2. Apocrine sweat gland - ducts empty into hair follicles
largely confined in axilla & genital area
begins to function during puberty under androgen
precise function (?)
activated by nerve fibers during pain, stress, sexual
foreplay
Composition and Function of Sweat
Composition
• Mostly water
• Some metabolic waste
• Fatty acids and proteins (apocrine only)
Function
• Helps dissipate excess heat
• Excretes waste products
• Acidic nature inhibits bacteria growth
 Odor is from associated bacteria
HAIR
• produced by hair bulb
• consists of hard keratinized epithelial cells
• melanocytes provide pigment for hair color
NAILS
• scale-like modifications of the epidermis
• heavily keratinized
• stratum basale extends beneath the nail bed
is responsible for growth of nail
• Colorless – due to lack of pigment
Nail Structures
 Free edge
 Body
 Root of nail
 Eponychium –
proximal nail fold that
projects onto the nail
body
The Skeletal System
• bone is a living tissue
• makes up 20% of the body’s weight
• provide strong, internal framework
• 5x stronger than steel
• 270: bones of newborn human
• 206: bones of adult human
Components:
• bones (skeleton)
• joints (articulations)
• cartilages
• ligaments – connect bones to other bones
• Tendon – connect bone to muscle
Functions of Bones
 Support of the body (framework)
 Surround & protect internal organs
 Provide attachment points for tendons
 Serve as levers (with help from muscles)
 Storage of minerals(calcium) and fats
 Manufacture of blood cell (red marrow)
Lever - projecting arm or handle that is moved to operate a
mechanism
Skeletal System
1. Axial – body’s long axis
a. Skull
b. Thorax
c. Vertebra
2. Appendicular
a. Upper Extremity
b. Lower Extremity
c. Pelvic Girdle
Two basic types of bone tissue
Compact bone
• Dense/hard
• smooth
• homogenous
Spongy (cancellous) bone
• Spiky, open appearance
• many open spaces, like a sponge
Long bones
• typically longer than wide
• has a shaft with heads at both ends
• contain mostly compact bone
Short bones
• generally cube-shape and small
• contain mostly spongy bone
Flat bones
• thin and flattened, usually curved
• thin layers of compact bone around a layer of spongy
bone
Irregular Bones
• irregular shape
• do not fit into other bone classification categories
Gross Anatomy of a Long Bone
Diaphysis
• shaft
• composed of compact bone
Epiphysis
• ends of the bone
• composed mostly
of spongy bone
Articular cartilage
• cover the external
surface of the
epiphyses
• decreases friction
at joint surfaces
Medullary cavity
• Cavity in the shaft
• Content:
- yellow marrow (mostly fat) in adults
- red marrow (for blood cell formation) in
infants
Bone Growth
2 Phases: Ossification & Remodeling
Ossification: birth to adolescence
• Fetal life: skeleton = hyaline cartilage
• Osteoblasts
- gradually replace the hyaline cartilage &
embeds within bone matrix
- matures in matrix
osteocytes
• Bone replaces cartilage
• Osteocytes - when osteoblast is surrounded by
matrix
• Osteoclast - contributes to bone repair and
remodeling
Remodelling: adulthood
• Strengthen bones/ parts subject to great stress
• Every bone in the body is completely replaced every 7
years
• Breakdown & build up slows down after age 30
Achieved by balanced activites of osteoclasts and
osteoblasts
Epiphyseal Disc
• growth plate
• epiphyseal plates allow for growth of long bone during
childhood
• end of adolescence: the growth plate hardens and
becomes ossified, growth stops
•
The Skull
• shapes the head and face
• constructed from 22 bones, 21 of which are locked
together by sutures (immovable joints)
• protects the fragile brain
• houses and protects the special sense organs for
taste, hearing, vision and balance
Divided into 2 groups:
1. Cranial Bones = 8 bones
2. Facial Bones = 14 bones
Cranial Bones
• 8 flat bones, all single except parietal & temporal
• support, surround and protect the brain
• form the roof, sides and back of cranium
• form the cranial floor (where brain rests)
Cranial bones:
1. Frontal
4. Occipital
2. Parietal
5. Ethmoid
3. Temporal
6. Sphenoid
Cranial Bones
1. Frontal bone (1):
- forms the forehead, anterior part of cranial floor, and roof
of orbits (eye sockets)
2. Parietal bone (2):
- form the roof and sides of cranium
3. Temporal bone (2): “temple”
- form the inferior lateral parts of cranium & part of cranial
floor
- External Auditory Meatus: an opening within the temporal
bone that direct sound to the inner ear
. Occipital bone (1):
- forms the posterior part of cranium & much of the cranial
floor
- Foramen Magnum: large opening through which the brain
connects to spinal cord
5. Ethmoid bone (1):
- forms part of cranial floor, medial walls of orbit, upper part
of nasal septum
6. Sphenoid bone (1):
- shaped like a “bat’s wing”
- articulates with, and hold together all the other cranial bones
Facial Bones (14)
1. Maxilla (2):
- form the upper jaw
- contain sockets for 16 upper teeth
- link all other facial bones except mandible
2. Zygomatic bone (2): “cheekbone”
- form the prominences of cheeks
- form part of lateral margins of orbit
3. Lacrimal bone (2):
- form part of medial wall of each orbit
4. Nasal bone (2):
- form the bridge of the nose
5. Palatine bone (2):
- form the posterior side walls of nasal cavity and posterior
part of hard palate
6. Inferior nasal conchae (2):
- form part of lateral wall of nasal cavity
7. Vomer:
- forms part of the nasal septum
8. Mandible:
- only skull that is able to move
- articulates with temporal bone – allowing mouth to open
and close
- provides anchorage for the 16 lower teeth
Sinuses
• air – filled spaces clustered around nasal cavity
• found in frontal, sphenoid, ethmoid, maxilla
• reduce the overall weight of skull
• give resonance and amplification to voice
The Fetal Skull
The fetal skull is large compared to the infants total body length
Fontanelles – fibrous membranes connecting the cranial bones
 allow the brain to grow

converted to bone within 24 months after
birth
The Hyoid Bone
• U shaped
• Found in the upper neck
• The only bone that
does not articulate
with another bone
• Serves as a
moveable base for
the tongue
The Vertebral Column
• backbone or spine
• consists of 26
irregular bones
• extends from skull
to pelvic girdle
• connected by
slightly movable
joints which allow
flexibility to rotate
& bend
(anteriorly,
posteriorly and
laterally)
• Makes up about
40% of body
height
• together with
sternum & ribs =
skeleton of trunk
• supports the skull,
• encloses &
protects the
delicate spinal
cord
• Provide attachment for ribs & attachment point for
muscles & ligaments supporting the trunk of the body
• Vertebrae separated by intervertebral discs
- forms slightly movable joint to allow
movement to backbone
- act as shock absorbers to cushion vertebra
against vertical shocks
The spine has a normal curvature
• Each vertebrae is given a name according to its
location
Cervical: neck region
- 7 vertebrae (C1-C7)
Thoracic: chest region
- 12 vertebrae (T1-T12)
Lumbar: lower back
- 5 vertebrae (L1-L5)
Sacrum: lower back
- forms posterior wall of pelvis
- 5 vertebrae at birth w/c fused
Coccyx: tailbone
- 4 vertebrae at birth w/c fused
The Bony Thorax (Thoracic Cage)
• chest region
• forms a cage to protect major organs
Composed of:
- Sternum
- Ribs
- Thoracic Vertebrae
Sternum: breastbone
- dagger-shaped bone
- location: midline of the anterior chest
Ribs: 12 pairs
- all attached posteriorly to thoracic vertebrae
True ribs: rib 1 – 7
- attached to sternum
False ribs: rib 8-10
- attached to cartilage of rib 7
Floating ribs: rib 11-12
Upper Limb (Forearm)
Radius: located on the
lateral or thumb side when
the palm of the hand is
facing forward.
Ulna: longer than radius
- located on the medial or
little finger side when palm
is facing forward
The Hand:
 Carpals – wrist
 Metacarpals –
palm
 Phalanges –
fingers
The Pelvic Girdle
• attaches the legs
to the trunk
• Composed of 2 coxal bones (hip bones) which is
made up of 3 pairs of fused bones, namely:
- Ilium
- Ischium
- Pubis
• total weight of the upper body rests on the pelvis
• Protects several organs
- Reproductive organs
- Urinary bladder
- Part of the large intestine
Pectoral (shoulder) Girdle
Composed of two bones
 Clavicle – collarbone
 Scapula – shoulder blade
- These bones allow the upper limb to have
exceptionally free movement
Upper Limb (Arm)
• The arm is formed by a single bone
Humerus - head of humerus allows for rotation
Ilium: forms the largest part of the hip bone
- each ilium articulates with sacrum at sacroiliac joint
posteriorly
Ischium: L-shaped, inferior & posteriorly located
- bears a person’s weight when they sit
Pubis (Or Pubic Bone): located anteriorly
- linked by fibrocartilage disc to forms a slightly
movable joint
Acetabulum:
- deep cup-like socket, located laterally
- produced by the meeting of the 3 hip bones
Lower Limbs: Thigh
The thigh has 1 bone
Femur – thigh bone
- head of femur inserts into the acetabulum of the hip
bone
Patella – "knee cap"
-
triangular bone located within a tendon that passes
over the knee.
Lower Limbs: Leg
The leg has two bones
Tibia: "shin bone"
- larger
Fibula
- Long and thin
Lower Limb: Foot
The foot
• Tarsal (7): ankle
• Metatarsals (5):sole
• Phalanges (5): toes
Joints or (Articulation)
Definition: part of skeleton where 2 or more bones meet
Functions:
 allow skeleton to move
 hold bones together
 provide stability to bones
 Classification of joints: based on amount of
movement the joint permits (**more movable joint =
less strength)
1. fixed
2. slightly movable
3. movable
Hyaline cartilage: glassy, hard-wearing coat that covers the
bone
- reduces friction between bones when they move
Synovial or joint cavity
- space between cartilage-covered bone ends
- outer layer: fibrous tissue inner layer: synovial
membrane
Synovial fluid – oily, yellowish liquid produced by synovial
membrane & secreted into synovial cavity
- reduces friction between bones by making hyaline
cartilage more slippery
1. Keratinization - cells change in shape and
undergo chemical reaction ; cells filled with
keratin and epithelial cells die
2. Hair shaft - above the surface of the skin
3. Hair matrix – growth zone of the hair
4. Melanin
5. Foramen magnum
6. Jaundice - yellowish skin color die to hepa or
liver problem
7. Two parts of skeletal: Axial/Appendicular
8. Axial skeleton – forms the longitudinal axis of
the body.
9. Melanin, hemoglobin, carotene
10. Formation of the bone after it got broken –
hematoma forms, fibrocartilage callus forms,
bony callus forms, bone remodeling occurs
11. Two layers of skin: epidermis/dermis
12. Two layers of dermis: papillary/reticular
13. Vertebrae: cervical (7vertebraeC1-C7), thoracic
(12vertebrae,T1-T2), lumbar (5vertebrae,L1-L5),
sacral (5fused vertebrae), coccyx (4fused
vertebrae)
14. Membranes
15. Location of adipose tissue
16. Fetal skull: 2 frontal bones. 2 parietal bones. 1
occipital bone/ Fontanelles – fibrous membranes
connecting the cranial bones
17. Ossification
18. Arrector Pili Muscle – goose bumps/ contracts
hair
19. Apocrine
20. Nutrients – Diffusion
21. Lunula – crescent shapes in nails
22. Short bone
23. Epiphyseal
24. Osteoblasts
25. Zygomatic Bone
26. Tubercle - a small rounded point of a bone
27. Femur