Science Olympiad Anatomy and Physiology (copy)

skeletal system functions

1. support/shape body

2. protection of internal organs

3. movement (with muscles)

4. storage (calcium, phosphorus, lipids)

5. blood cell production

number of bones

-206 bones, half in hands/feet -80 bones in axial skeleton -126 bones in appendicular skeleton

axial skeleton

skull, ossicles of middle ear, hyoid bone, thorax/chest, vertebral column

appendicular skeleton

-upper (64): shoulder girdle, arms, hands -lower (62): pelvic girdle, legs, feet

long bones

-longer than they are wide, shaft

short bones

-roughly cube-shaped -ex: ankle/wrist

sesamoid bones

-short bones within tendons -ex: patella

flat bones

-thin, flat, often curved -ex: sternum, scapulae, ribs, must skulls

irregular bones

-odd shapes, don't fit into other categories -ex: hip bones, vertebrae

types of vertebrae

-cervical (7): atlas, axis -thoracic (12) -lumbar (5)

cervical vertebrae

-atlas: 1st, supports head -axis: 2nd, dens pivots to turn head

thoracic vertebrae

long spinous processes; rib facets

lumbar vertebrae

large bodies; thick, short spinous processes

types of joints

ball and socket, pivot, saddle, hinge, elipsoid/condyloid, plane/grinding (vertebrae)

osteoblasts

bone forming cells synthesize/secrete unmineralized ground substance; found in areas of high metabolism within bone

osteocytes

mature bone cells made from osteoblasts that have made bone tissue around themselves; maintain healthy bone tissue by secreting enzymes and controlling bone mineral content; also control calcium release from bone tissue to the blood

osteogenic cells

responds to trauma (ex: fractures) by giving rise to bone-forming/bone-destroying cells

osteoclasts

bone absorbing cell, large cells that break down bone tissue; important to growth, healing, remodeling

bone lining cells

made from osteoblasts along surface of most bones in adults; though to be able to regulate movement of calcium/phosphate into/out of bone

long bone structure

-compact bone: outer layer, haversian system -spongy bone: ends of long bones -cartilage

hematopoiesis

formation of blood cells; takes place mainly in red marrow

red marrow

-infants: found in bone cavities; replaced by yellow marrow for fat storage -adults: limited to spongy bone in skull/ribs/sternum/clavicles/vertebrae/pelvis; makes red/white blood cells and blood platelets

cartilage

mostly water; no blood vessels/nerves; tough, resilient; forms from chondroblasts; heal poorly

hyaline cartilage

fine collagen fiber matrix, most abundant; found in articular cartilages (movable joint), costal cartilages (connect ribs to sternum), respiratory cartilages ( larynx, upper respiratory passageways), nasal cartilages

elastic cartilage

similar to hyaline cartilage, more elastic fibers (very flexible); found in external ear/epiglottis (larynx covering)

fibrocartilage

rows of chondrocytes with thick collagen fibbers; highly compressible with great tensile strength found in menisci of knee, intervertebral discs, public symphysis

bone repair sequence

1. injury: broken blood vessels, hematoma

2. invasion of blood vessels/generalized cells; 2-3 days

3. fibroblasts develop; 1 week

4. chondroblasts develop

5. callus forms; 4 weeks

6. remodeling with osteoclasts; 8 weeks

disease/injury levels

-osteoarthritis -osteoporosis -fractures (pictures/x-rays) -disc herniation -scoliosis -ACL/MCL injuries

muscular system functions

1. stabilizing joints

2. maintaining posture

3. producing movement

4. moving substances within body

5. stabilizing body position/regulating organ volume

6. producing heat (85%)

excitability

ability to receive/respond to stimuli

contractility

ability to shorten/thicken

extensibility

ability to stretch

elasticity

ability to return to its original shape after contraction/extension

skeletal muscle

-attached to bone -move whole body -multiple/peripheral nucleus -voluntary control -striations -cylindrical shape -nearly 650

smooth muscle

-on hollow organs/glands/blood vessels -compress tubes/ducts -single/central nucleus -involuntary control -no striations -spindle shape

cardiac muscle

-heart -heart contraction to propel blood -single/central nucleus -involuntary control -striations -branched shape

skeletal muscle movement

-work in pairs -most extend from one bone across joint to another; one bone more stationary than another -bends skeleton at movable joints -pull of contraction causes bending; one group contracts, other stretches

tendons

-made of dense fibrous connective tissue shaped like heavy cords anchor muscles firmly to bone -may be injured

origin

-attachment to more stationary bone by tendon closest to body/muscle head/proximal -remains stationary during movement

insertion

-attachment to more movable bone by tendon at distal end -moves during movement

skeletal muscle anatomy

-each muscle: 1000s of fibers in a bundle; run from origin to insertion; bound together by connective tissue containing blood vessels/nerves -each muscle fiber: many nuclei, extensive endoplasmic/sarcoplasmic reticulum, many thick/thin myofibrils running lengthwise, many mitochondria

sarcomere

basic functional unit of muscle fiber; consists of array of thick/thin filaments between 2 Z disks

thick filaments

-with myosin (protein) molecules

thin filaments

with actin (protein) molecules, smaller amounts of troponin/tropomyosin

striations

dark A bands and light I bands

A bands

bisected by H zone, with M line/band running through center of H zone

I band

bisected by Z disk/line

myosin head

globular subunit inside myosin molecules; has binding sites for actin molecules of thin filaments/ATP; activating muscle fiber causes myosin heads to bind to actin molecules pulling short filament past thick filaments

linkages

break/reform using ATP energy further along thick filaments

ratchet-like action

pulls thin filaments past thick filaments

individual filaments

no shortening, thickening, folding

muscle contracts

-width of I bands/H zones decrease; Z disks to come closer together -no change in width of A band because thick filaments don't move

muscle relaxes/stretches

-width of I bands separate as thin filaments move apart -thick filaments still don't move

strain

injuries from overexertion/trauma; involve stretching/tearing of muscle fibers; often accompanied by pain/inflammation of muscle/tendon

sprain

injury near join, involves ligament

cramp

painful muscle spasms/involuntary twitches

stress-induced muscle tension

may cause back pain/headaches

poliomyelitis

viral infection of nerves that control skeletal muscle movement

muscular dystrophies

-most commonly caused by mutation of gene for protein dystrophin which helps in attaching/organizing filaments in sacromere -Duchenne Muscular Dystrophy/Becker Muscular Dystrophy: 2 most common types -gene located on X chromosome; sex-linked disorder

myasthenia gravis

-autoimmune disease affecting neuromuscular junction -affects ability of impulse to cause muscle contraction -acetylcholinesterase: inhibitor, can temporarily restore contractibility

effects of exercise on muscular system

-muscles are more effective/efficient -tendons are stronger/thicker -high intensity exercise for short duration: produces strength, size, power gains -low intensity exercise for long duration: endurance benefits -beter tone/state of readiness to respond -good posture, enables muscles to work effectively, helps prevent injury

parts of integumentary system

skin, hair, nails, subcutaneous tissue below skin, assorted glands

skin functions

1. protection from injury

2. protection against infection

3. regulates body temperature

4. regulates water loss

5. chemical synthesis

6. sensory perception

serous membrane

-lines body cavities that have no opening to outside -secrete watery fluid (serous fluid) that lubricates surfaces

mucous membrane

-line cavities/tubes that open to outside

synovial membrane

-form inner lining of joint cavities -secrete thick fluid (synovial fluid)

cutaneous membrane

-aka skin

epidermis

-covers internal/external surfaces of body

dermis

-inner layer; contains accessory skin -2nd deepest part of skin -composed mainly of connective tissues (collagen, elastic fibers)

hypodermis/subcutaneous layer

-attaches skin to underlying organs/tissues

thin skin

-1-2 mm on most of body; 0.5 mm on eyelids -hairy; covers all parts of body except palms/soles

thick skin

-up to 6 mm thick on palms/soles -hairless; covers palms/soles

keratinocytes

-90% of epidermal cells are keratinized -contain keratin (fibers protein) -protects/waterproofs skin

melanocytes

-8% of epidermal cells -produces melanin -contributes to skin color -absorbs UV light

langerhans cells

-arise from red bone marrow, migrate to epidermis -constitute small portion of epidermal cells -participate in immune responses -easily damaged by UV light

merkel cells

-least numerous -found in deepest layer of epidermis -along with tactile discs, function in sensation of touch

stratum corneum

-nuceli/organelles destroyed by lysosomes -cells fill with keratin

stratum lucidum

-only found in palms/soles -3-5 layers of clear, flat, dead keratinocytes -dense packed intermediate filaments -thick plasma membranes

stratum granulosum

-cells start to become keratinized -secretes lipid-rich secretion that acts as water sealant

stratum spinosum

-8-10 layers of keratinocytes -skin both strength/flexibility

stratum basale

-aka stratum germinatum -where new cells are formed

growth of epidermis

-newly formed cells in stratum basale undergo keratinization as they're pushed to surface; accumulate more keratin during the process; undergo apoptosis (death); eventually slough off/are replaced -take about 4 weeks -rate of cell division in stratum basale increase during injury

papillary layer

-surface area increased due to projections (dermal papillae) which contains capillaries/tactile receptors -epidermal ridges conforms to dermal papillae

reticular layer

-contains hair follicles, nerves, sebaceous/sudoriferous glands

hypodermis

-subcutaneous; attaches skin to underlying organs/tissues -not part of skin; lies below dermis -contains connective/adipose tissues (subcutaneous fat) for insulation -infants/elderly have less than adults, more sensitive to cold

skin color

-genetic factors: skin pigmentation; all humans have same number of melanocytes; melanin produced is controlled by certain genes -environmental factors: exposure to sunlight -volume of blood: hemoglobin in blood

albinism

lack of pigment

melanin

-located mostly in epidermis -eumelanin: brownish black -pheomelanin: reddish yellow -fair-skinned people have more pheomelanin; dark-skinned people have more eumelanin

environmental factors that affect melanin production

-UV light: increases enzyme activity in melansomes; increased melanin production -tan: amount of melanin increases; darkness of melanin -eumelanin: protection from UV radiation; pheomelin breaks down with too much UV -too much UV: may cause skin cancer

carotene

-yellow-orange pigment -precurser of vitamin A, important for vision -found in stratum corneum, fatty areas of dermis, hypodermic layer

hemoglobin

-oxygen carrying pigment in red blood cells

friction ridges

-markings on fingertips characteristic of primates -ability to manipulate objects more easily -fingerprints: friction ridge skin impressions

flexion lines

-on flexor surfaces of digits, palms, wrists, elbows, etc -skin is tightly bound to deep fascia at these points

freckles

-flat melanized patches vary with heredity/exposure to sun

moles

-elevated patch of melanized skin with hair; mostly harmless beauty marks

aging skin

-20s: effects of aging being to be visible -stem cell: activity declines; thin skin, repair difficult -epidermal dendritic cells: decrease; reduced immune response -vitamin D3: production decreases; calcium absorption declines; brittle bones -glandular activity: declines; skin dries, body can overheat -blood supply to dermis: declines; tend to feel cold -hair follicles: die, produce thinner hair -dermis: thins, becomes less elastic, causes wrinkles

skin derivatives

during embryonic development, thousands of small groups of epidermal cells from stratum basale push down into dermis to for hair follicles/glands

hair and nails function

1. hair on head protects scalp from injury/sunlight

2. eyelashes/eyebrows protect eyes

3. nostril/ear hairs protect from foreign particles

4. help in sensing light touch due to touch receptors associated with hair root plexuses

5. grasping objects

6. manipulating objects

7. protects ends of digits from trauma

8. scratching

shaft

portion of hair that projects from skin surface

root

-portion of hair deep to the shaft penetrating the dermis -3 layers: medulla, cortex, cuticle