Exam 2 Anatomy and Phys

Sebaceous Glands

holocrine glands that produce sebum, an oily substance that keeps hair and skin soft, pliable, and waterproof

·      Sebum is discharged into a hair follicle and onto the hair itself

·      Acne results from excess sebum

Merocrine (Eccrine) glands-

most common type

·      Discharge secretions directly into surface of the skin

·      Respond to increase in body temp elevated by environmental heat or exercise

·      Common on forehead, neck, and back

·      Cause sweat on hands when one is emotionally stressed

·      Major function: thermoregulation

 

Apocrine Sweat Glands

·  Coiled, tubular glands that release their secretion into hair follicles in armpits, around nipples, and groin

·      Produce a sticky, cloudy, and odorous secretion (contains proteins and lipids)

·      Become active around puberty

Ceruminous Glands

· Modified apocrine sweat glands located only in the external acoustic meatus (ear canal) where their secretion forms cerumen (earwax)

·      Cerumen and hairs in the meatus trap foreign particles and keep them from reaching the eardrum

Mammary Glands

·      Modified apocrine sweat glands

·      Become functional in pregnant and lactating females; regulated by hormones

Hair

·      Each hair follicle has or or more sebaceous glands

·      Arrector pili muscle- smooth muscle that is attached to each hair follicle

·      When muscle contracts, makes hair stand on end (goose bumps)

Functions of Hair

1.     Protection

From sunburn and injury

2.     Heat retention

3.     Sensory reception

Hair has tactile receptors that detect light touch

4.     Visual identification

Determine age and sex

5.     Chemical signal dispersal

Hairs disperse pheromones

Nails

·      Protective coverings on the ends of fingers and toes

·      Consists of:

1.     Free edge

2.     Nail body- dead, tightly compressed cells packed with keratin

3.     Nail root- proximal part embedded in the skin

Nail bed

skin under nail body/plate which contains the deeper. Living cells of epidermis

Nail matrix

actively growing part of the nail

Lanula

white, half-moon shaped area composed of epithelial cells

Eponychium (cuticle)-

 narrow band of epidermis extending from the margin of the nail wall onto the nail body

Hyponychium

 region of thickened stratum corneum over which the free nail edge projects

Functions of integumentary system

 

·      Protective covering

·      Repels water

·      Helps regulate body temperature

·      Houses regulate body temp

·      Houses sensory receptors

·      Contains immune system cells

·      Synthesizes chemicals, including vitamin D

Epidermis

·      Superficial layer

·      Stratified squamous epithelium

Dermis

·      Deep layer

·      Thick than epidermis

·      Made up of connective tissue containing irregular connective tissue

·      Contains many nerves and blood vessels

Subcutaneous Layer (hypodermis)

·      Found deep to dermis

·      Not considered part of integument

·      Compound of areolar tissue and adipose tissue

·      Binds to skin to underlying organs

Epidermis Functions

1.     Protection

2.     Prevention of water loss

3.     Metabolic regulation

4.     Secretion and Absorption

5.     Immune function

Layers or Strata

1.     Stratum Basale (basal layer)

Deepest layer

2.     Stratum Spinosum (spiny layer)

3.     Stratum Granulosum (granular layer)

4.     Stratum Lucidum (clear layer)

5.     Stratum Corneum (hornlike layer)

Stratum Basale

·      Deepest epidermal layer

·      Single layer of cells tightly attached to basement membrane that separates epidermis from dermis

·      Contain 3 types of cells:

1.     Keratinocytes

Cells divide and generate new cells that replace dead keratinocytes shed from surface

2.     Melanocytes

Produce and store pigment melanin in response to UV light exposure

3.     Tactile Cells

Release chemicals that stimulate nerve endings when compressed providing info about objects touching the skin

Nourished by dermal blood vessels

Stratum Spinosum

·      Contains 2 types of cells:

1.     Keratinocytes (several layers of non-dividing keratinocytes which attach to their neighbors by desmosomes)

2.     Epidermal dendritic cells- immune cells that help fight infection in the epidermis

Stratum Granulosum

·      Consists of 3-5 layers of keratinocytes

·      Keratinization begins within this stratum

Keratinocytes fill up with the protein keratin, which causes the cell’s nucleus and organelles to disintegrate and the cell dies. Keratinization is complete when cells reach the superficial epidermal layers, very strong and waterproof

Stratum Lucidum

·      Thin, translucent region of about 2-3 layers

·      Found only in thick skin within the palms of the hands and soles of feet

·      Keratinocytes within this layer are flattened and filled with eleidin; protein which protects the skin from UV light

Stratum Corneum

·      Most superficial layer

·      Consists of about 20-30 layers of dead, scaly, interlocking keratinized cells

·      Cells are anucleate and tightly packed together

Melanocytes

Produce and store pigment melanin in response to UV light exposure

Skin color

·      Skin color is influenced by the presence of pigments

Hemoglobin, melanin, carotene

Hemoglobin

- protein present in red blood cells that exhibit a bright red color when bound to oxygen

Melanin

brown, yellow-brown or black pigment produced by melanocytes

Carotene

orange- yellow pigment that accumulates

Genetic Factors of skin

·      Genetically programmed

·      Number of melanocytes is fixed

·      Dark skin- dark melanin and large melanosomes

·      Light skin- light melanin and small melanosomes

·      Albinism- people who inherit mutant melanin genes have nonpigmented skin

Environmental factors of skin

·      Tanning increases pigmentation

·      Stimulates melanocytes.

·      Overexpose leads to skin cancer

Physiological Factors of skin

Blood

·      Oxygenated=pink

·      Deoxygenated=blue (cyanosis)

Blood vessels

·      Dilation=blush

Due to overheating, embarrassment or after consuming alcohol

·      Constriction=pale

Vitamin D Synthesis

·      UV exposure

·      Cholecalciferol (Vitamin D3) is produced.

·      Kidney uses calcitriol to absorb calcium and phospherus by the small intestine

·      Inadequate supply of calcitriol leads to impaired bone growth and maintenance.

Fine Touch

·      Tactile corpuscles

·      Merkel cells

Deep pressure

Lamellated (Pacinian) corpuscles

Temperature and pain

Free nerve endings

Structure of hair

·      Each hair follicle has or or more sebaceous glands

·      Arrector pili muscle- smooth muscle that is attached to each hair follicle

·      When muscle contracts, makes hair stand on end (goose bumps)

Sebaceous Glands

holocrine glands that produce sebum, an oily substance that keeps hair and skin soft, pliable, and waterproof

·      Sebum is discharged into a hair follicle and onto the hair itself

·      Acne results from excess sebum

Merocrine (Eccrine) glands

most common type

·      Discharge secretions directly into surface of the skin

·      Respond to increase in body temp elevated by environmental heat or exercise

·      Common on forehead, neck, and back

·      Cause sweat on hands when one is emotionally stressed

·      Major function: thermoregulation

Apocrine Sweat Glands

·      Coiled, tubular glands that release their secretion into hair follicles in armpits, around nipples, and groin

·      Produce a sticky, cloudy, and odorous secretion (contains proteins and lipids)

·      Become active around puberty

Repair and Regeneration

Damaged tissues are repaired 2 ways:

Regeneration: replacement of damaged or dead cells with the same cell type

·      Restores organ function

Fibrosis: Occurs when regeneration is not possible; the body fills in the gap with scar tissue

Wound Healing

1.     Bleeding occurs in the wound; blood brings clotting proteins, leukocytes and antibodies

2.     Blood clot forms, Macrophages and neutrophils clean the wound of cellular debris

3.     Cut blood vessels regeneration and grow in the wound. Granulation tissue forms. Macrophages remove the clotted blood. Fibroblasts produce new collagen fibers

4.     Epithelial regeneration of the epidermis occurs. The connective tissue is replaced by fibrosis

Superficial partial thickness (1st degree)

o   Involves only epidermis

o   Minor sunburn

o   May have reddening, swelling, pain

Deep partial thickness (2^nd Degree)

·      Destroys epidermis and some dermis

·      Blisters appear, pain, swelling

·      Skin usually heals completely

Full-thickness burn

Third degree

·      Injured skin becomes fry and leathery, and may vary in color from red to black to white

·      Epidermis and dermis are destroyed

·      Swelling and numbness

·      May require grafting

o   Autograft-using skin from uninjured part of the body

o   Homograft- cadaver skin used to temporarily cover the wound and help prevent infection

o   Xenograft- graft from another species

Hyaline and fibrocartilage

What are the two types of cartilage in the skeletal system

Hyaline cartilage

Costal cartilage, articular cartilage, and epiphyseal plate

Fibrocartilage

Intervertebral discs, pubic symphysis and menisci

80 bones in the Axial skeleton and 126 bones in the Appendicular skeleton. Axial is the head, neck, back and chest. Appendicular is the upper and lower extremities

Difference between the appendicular and axial skeleton

Functions of the skeletal system

1.     Structural support

2.     Protection

3.     Blood cell production (hemopoiesis)

4.     Storage of minerals and energy reserves

5.     Movement (leverage)

Parts of a long bone

Epiphysis, Diaphysis, Metaphysis, Periosteum, Medullary Cavity, Blood Supply

Epiphysis

expanded portion at each end

·      Coated with hyaline cartilage (articular cartilage)

·      Consists of spongy bone (trabecular bone) with a thin covering of compact bone

Diaphysis

shaft of bone

Metaphysis

connects epiphysis to the shaft

Periosteum

tough covering that encloses bone except for area covered by articular cartilage

·      Consists of 2 layers:

·      Outer layer protects bone from surrounded structures, anchors blood vessels and nerves, and serves as an attachment for ligaments and tendons

·      Inner cellular later

Medullary Cavity

hollow chamber in the diaphysis of long bone

·      Endosteum- lines this cavity

·      Marrow fills cavity (red and yellow marrow)

Blood Supply

·      Diaphysis: nutrient artery/ nutrient vein

·      Metaphysis: metaphyseal artery/ metaphyseal vein

Osteoprogenitor Cells

·      Stem cells that divide to produce daughter cells which turn into osteoblasts

·      Important in the repair of a fracture

·      Located in periosteum and endosteum

Osteoclasts

cells that break down bone

Osteoblasts

cells that form bone (beginning of bone)

·      Make and secrete the proteins and other organic components of the bone matrix- osteoid

·      Calcium salts are deposited into matrix converting osteoid to bone

·      Osteocytes develop from osteoblasts that are completely surrounded by bone matrix

Osteocytes

mature bone cells (detects stress)

·      Located in lacunae

·      Form concentric circles around a central canal

·      Transport nutrients and wastes through small channels called canaliculi

·      Maintain matrix and repair of damaged bone

Compact Bone

·      Osteon- basic structural unit of compact bone

·      Cylindrical shaped unit, oriented parallel to the diaphysis

·      Central Canal contains blood vessels and nerve fibers

Spongy bone

·      Highly porous

·      Found in short, flat and irregular bones

·      Also found in epiphyses of long bones and around medullary canal

·      Osteocytes lie within trabeculae

·      Cells get nutrients from substances diffusing into the canaliculi that lead to the surface

Red bone marrow

produces blood cells

Yellow bone marrow

stores adipose (energy)

Matrix in spongy bone is called trabeculae

it contains bone marrow

Intramembranous Ossification

·      Form broad, flat bones of the skull, facial bones, central part of clavicle.

·      These bones start as membrane-like layers of connective tissue collect around blood vessels

·      Osteoblasts form, which deposit bony matrix

Endochondral Ossification

1.     Formation of cartilage model

·      Chondroblasts secrete cartilage matrix and form hyaline cartilage

2.     Growth of Cartilage

·      Chondroblasts embed and become chondrocytes. They grow, then burst and disintegrate, leaving cavities within the cartilage.

·      Cartilage matrix begins to calcify

·      Perichondrium convert to osteoblasts and ossifies

3.     Development of Primary Ossification Center

·      Blood vessels penetrate cartilage

·      Fibroblasts differentiate into osteoblasts and begin producing spongy bone in the middle

4.     Development of Secondary Ossification Centers

·      Blood vessels penetrate the epiphysis

·      Epiphysis is filled with spongy bone

·      Osteoclasts- dissolve spongy creating the medullary cavity

5.     Formation of articular cartilage and epiphyseal plate

·      Articular cartilage remains at the ends of each epiphysis

·      Epiphyseal cartilage separates the epiphyseal cartilage separates the epiphysis from the diaphysis

Appositional Bone Growth

- growth at outer surface

Adding matrix:

o   Osteoblasts add matrix to the surface

o   New osteon- osteoblast is trapped and becomes osteocyte

o   Osteoclasts remove lamellae at the inner surface

Interstitial growth

1.     Chondrocytes undergo mitosis

2.     2 cells occupy on lacuna; now called chondroblasts

3.     Chondroblasts synthesize and secrete new matrix, pushes apart and then reside in ow lacuna (chondrocytes)

4.     Cartilage continues to grow in the internal region as chondrocytes continue to produce more matrix

Minerals

Calcium, Phosphorous

Vitamins

o   Vitamin A- necessary for normal osteoblast and osteoclast activity

o   Vitamin C- required for collagen synthesis

o   Vitamin D- necessary for proper absorption of calcium of the gastrointestinal tract

Bone Remodeling

Continually renewed

o   Osteoclasts remove old

o   Osteoblasts form new

Remodeling

o   Prevent deterioration.

o   Response to stress

o   Exercise

o   No stress=bone loss

o   Fixes bone injuries (fractures)

o   Calcium homeostasis

calcium homeostasis

o   Bone- contains 99% of the body’s calcium

o   Regulation blood level calcium

o   Affect resorption/ deposition

o   Controlled by two hormones

1.     Calcitonin

2.     Parathyroid hormone

Calcitonin

Result of Blood calcium decreasing

Parathyroid hormone

Result of Blood Calcium increasing

Bones and Aging

1.     Bone mass loss

Demineralization

2.     Brittleness

Decrease in rate of protein synthesis by osteoblasts

Osteoporosis

·      Reabsorption > Deposition

Brittle bones

Shrinkage of vertebrae

Height loss

Hunched backs

·      Women are at a greater risk

Calcium supplements

Weightbearing exercise

(Wolff’s Law)

·      Imbalance between bone formation and bone reabsorption

More osteoclast activity than osteoblast

·      Bone density is decreased

Fracture risk is increased

Synarthrosis

immobile

Amphiarthrosis

slight movement

Diarthrosis/synovial

freely movable

Fibrous joints

held together by dense fibers (connective tissue)

Cartilaginous joints

fiber cartilage and hyaline cartilage

Synovial

fluid filled joint cavity that separates the bones (elbow, knee, shoulder)

Synovial joint

fluid filled joint cavity that separates the bones (elbow, knee, shoulder)

Bursa

small, fluid- filled sac found in some synovial joints

-       Cushion and aid the movement of tendons that glide over body parts or over other tendons

Fat pads

localized mass of adipose tissue covered by layer of synovial membrane

-       Acr as packing material and provide some protection for the joint

Meniscus

disc of fibrocartilage in some synovial joints

Synovial Joints

Accessory structures

·      Bursa

·      Fat pads

·      Meniscus

Plane joints

(plantar or gliding) (least mobile)

-       Articulating surfaces are flat or slightly curved

-       Allow sliding or back-to-back movement

-       Most in wrist and ankle, also SI joint

Hinge Joint

-       Convex surface of one bone fits with concave surface of another

-       Elbow, knee (modified), joints in phalanges. (like a door, one plane)

Pivot Joint (rotation)

-       Cylindrical surface of one bone rotates within a ring formed by bone and a ligament

-       Proximal radial-ulnar joint, C1 and C2 (atlas/axis) (shaking head)

Condylar (condyloid or ellipsoid) joint-

ovoid condyle of one bone fits into the elliptical cavity of another ( motion in 2 axis/2 planes)

-       Allows many motions, except rotation

-       Metacarpophalangeal (MCP joints) (knuckles) out and in or back and forth

Saddle Joint

-       Between bones with bone concave and convex surfaces (forward/ backward, out/ in, rotate in slightly)

-       Joint in thumb between metacarpal and trapezium (carpal) (thumb)

Ball and socket joint (3 planes)

-       Consists of bone with spherical end articulating with another bone with a cup-shaped cavity

-       Hip, shoulder (glenohumeral joint)

-       Most movable, least stable

Flexion

bending parts at a joint so that the angle between them decreases and the parts come closer together

Extension

straightening parts at a joint so that the angle between them increases and the parts move farther apart

Hyperextension

excess extension of the parts of a joint, beyond anatomical position (looking up)

Lateral flexion

vertebral column moves in a lateral direction along a coronal plane (neck or trunk)