Science Olympiad Anatomy and Physiology - #2

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

-lower (62): pelvic girdle, legs, feet{}long bones

-longer than they are wide, shaft + 2 ends

-ex: arms/legs, except wrist/ankle/patella{}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

-spongy bone: ends of long bones

-cartilage{}hematopoiesis

formation of blood cells; takes place mainly in red marrow{}red marrow

-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

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

-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

-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

-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

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

-secrete thick fluid (synovial fluid){}cutaneous membrane

-aka skin{}epidermis

-2nd deepest part of skin

-composed mainly of connective tissues (collagen, elastic fibers){}hypodermis/subcutaneous layer

-attaches skin to underlying organs/tissues{}thin skin

-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

-not part of skin; lies below dermis