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MCAT Biology > Chapter 8 > Flashcards

Chapter 8 Flashcards

1
Q

skeletal muscle

A

voluntary muscle tissue

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2
Q

tendon

A

how muscle attaches to bones

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3
Q

ligament

A

connects bone to bone

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4
Q

agonist

A

(muscle responsible for movement contracts)

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5
Q

antagonist

A

stretches ;

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6
Q

when antagonist contracts

A

bone moves in the opposite direction which stretches the agonist

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7
Q

synergistic

A

assist the agonist by stabilizing the origin bone or by positioning the insertion bone during the movement

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8
Q

contraction of skeletal muscle

A

may squeeze blood and lymph vessels aiding circulation, produce a lot of heat

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9
Q

shivering

A

controlled by the hypothalamus, rapid contraction of skeletal muscle to warm the body

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10
Q

sarcomere

A

smallest functional untit of the skeletal muscle

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11
Q

thick and thin filament

A

laid side by side to form a cylindrical segment

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12
Q

myofibril

A

sacromeres are positioned end to end to form this

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13
Q

SR

A

surround the myofibril, specialized type of ER

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14
Q

skeletal muscle

A

multinucleate

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15
Q

sarcolemma

A

wraps several myofibrils together to form a muscle cell or muscle fiber

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16
Q

thick filament

A

sarcromere made up of myosin, several long mysoin molecules wrap around each other to form one thick filament

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17
Q

thin filament

A

composed mainly of a polymer of the globular protein actin, attached to actin are troponin and tropomyosin

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18
Q

contraction of skeletal muscle 1

A

tropomyosin covers the active site on the actin preventing the myosin head from binding. mysoin head remains cocked in a high energy position with a phosphate and ADP group attached

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19
Q

contraction part 2

A

in the presence of calcium tropnin pulls tropomyosin back exposing the active site, allowing the myosin head to bind to theactin

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20
Q

contraction part 3

A

the myosin head expels a phospahte and ADP and bends into a low energy position dragging the actin along with it – power stoke : causes muscle contraction

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21
Q

contraction part 4

A

ATP attaches to myosin head –> this releases the myosin head from the active site, which is covered immediately by tropomyosin

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22
Q

contraction part 5

A

ATP splits to inorganic phosphate and ADP causing the musoin head to cock into the high erngy position

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23
Q

muscle contraction

A

begins with AP

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24
Q

neuromuscular synapse

A

neuron attaches to a muscle cell forming a neuromuscle synapse

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25
AP of the neuron
release acetylcholine into the synaptic cleft
26
acetylcholine
activates ion channels in the sarcolemma of the muscle cell creating an AP, AP moves deep into the muscle cell via small tunnels in the membrane called T-tubules
27
t-tubules
allow for a uniform contraction of the muscle by allowing the AP to spread through the muscle cell more rapidly
28
AP
transferred to SR which becomes permeable calcium ions, begins muscle cycle, at the end Ca is pumped back into the SR
29
motor unit
neuronand the muscle fibers that it intervates; independent of each other , smaller ones are first to activated -- results in a smooth increase in the force generated by the muscle -- fingers have smaller motor units
30
slow twitch muscle fibers
have large amounts of myoglobin (like hemoglobin with 1 protein subunits), large amounts of mitoochondria, split ATP at a slow rate, slow to fatigure, have slow contraction velocity , postural muscles
31
type II A (fast twitch A fibers)
red, split ATP at a high rate, contract more rapidly, slow to fatigue but not as resistant as type I -- upper muscles
32
type II B
low myoglobin content, appear white, contain large amounts of glycogen -- upper arms
33
cardiac muscle
striated, one nucleus, separated by an intercalated disc (contain gap juctions, help AP to spread from one cardiac cell to another), bigger mitochondria and more of the, like a net (contracts on itself, not connectd to bone), involuntary
34
hypertrophy
no mitosis, repetitive contraction the muscle changes, cell diameter and change in muscle confirmation, sarcomeres lengthen, # of sarcomeres and mitochondria increase
35
smooth muscle
involuntary (ANS), thick, thin and intermediate filaments(attached to dense bodies throught cell), contraction -- smoothe muscle shrinks length wise, thin and think filaments attached to the intermediate filaments -- pull dense bodies
36
single unit smooth muscle
visceral, connected by gap jucntions AP from a single neuron through a larger group of cell allowing the cells to contract as single unit, found in small arteries, viens, stoach, uterus and urinary bladder
37
multiunit smooth muscle
attached directly to a neuron, can contract independently of other muscle fibers in the same location, found in the larger arteries, bronchioles, pili muscles attached to hair follices and the iris
38
smooth muscle extra info
contracts or relaxes in the presence of hormones, change in pH, oxygen and carbon dioxide levels, temp and ion concentration
39
bone
support of soft tissue, protection of internal organ, body movement, mineral and energy storage (adipose cells), blood ell protection
40
osteoblasts
secrete collage and organic compounds, no mitosis, enveloped by the materials they release -- differentiate into osteocytes
41
osteocytes
incapable of mitosis, exchange nutrients and waste materials in the blood
42
osteoclasts
resorb blood matrix, release minerals back ito the blood
43
spongy bone
red bone marrow, site of red blood cell developmenet
44
compact bone
surround the medullary cavity which holds yellow bone marrow -- contains adipose cells for fat storage
45
remodeling process
osteoclasts burrow Haversian canals in the compact bone, then osteoblasts lay down new matrix onto the tunnel walls forming lamellae, osteocytes trapped between the lamellae exchange nutrients via canaliculi. Haversian canals contain blood and lymph vessels and are connected by Volkmann's canals.
46
osteon
lamella and Haversian canal system
47
Caclium in the blood
bound mostly by proteins and a little bit by phosphates
48
too much calcium
hypoexcitable membranes -- lethargy, fatigure memory loss
49
too little
cramps and convulsion
50
most Ca in the body
in hydroxyapatite , lie along side collage fibers give bone great compressive strength
51
someCa
exists in the bone of slightly soluble calcium salts , these salts buffer ca levels
52
bone acts as
storage site for calcium and anion
53
long bone
shaft curved for strength, composed of compact and spongy bone -- leg arm finder and toe bones
54
short bones
cuboidal -- ankle and wrist bones
55
flat bones
made from spongy bone surrounded by compact bone, provide large areas for muscle attachement and organ protection -- skull, sternum, ribs and shoulder blades
56
irregular bones
has an irregular shape and variable amounts of compact and spongy bone
57
cartilage
flexible, resilent connective tissue, made mostly of collagen, tensile strength, no blood vessels or nerves, hyaline cartilage -- reduces friction and absorbs shock in joings
58
fibrous joings
occur between 2 bones held closely and tightly together by fibrous tissue premitting little or no movement. skull bones form fibrous joints with each other; teeth form fibrous joints with the mandible
59
cartilagous joints
little or no movement, occur btwn two bones tightly connected by cartilge such as the ribs and the sternum or public symphysis in the hip bone
60
synovial joints
seprate for the cartilage by a capsule filled synovial fluid -- provides lubrication and nourishment to the cartilage, contains phagocyotic cells that remove microbes and particles which result from wear and tear from joint movement. allow for wide range of movement
61
skin
thermoregulation (blood shunted away from the capillaries), protection, enviornmental sensory input, excretion, immunity, blood reservoir, vitamin D synthesis
62
epidermis
avascular, four cell types 1. keratinocytes -- produces kertain that waterproofs the skin 2. melanocytes transfer melanin to kertainocyes 3. langerhans interact with helper T-cells of the immune system 4. merkel cells attach to sensory neurons and function in the senation of touch
63
subcutaneous tissue
heat insulator, maintains core body temp on cold days while the skin apporaches the temp of the environment
64
layers of the epidermis
deepest layer-- merkel cell and stem cells, stem cells continually divide to produce kertainocytes and other cells, keratinocytes are pushed to the top layer, as they rise -- get keratin and die -- when they become the outermost later of the skin, slough off the body -- takes2-4 weeks. outermost-- 25 to 30 layers of flat dead cells.
65
callus
exposure to friction or pressure stimulate the epidermis to thicken
66
dermis
mesodermal cells--embedded by blood vessels, nerves, glands and hair folicles ; collagen and elastic fibers provide skin with strength, extensibility and elasticity, thick in the palsm and soles
67
hair
kertainized cells held closely together. most hairs associated with oil gland , smooth muscle also associated with each hair stands hair up when skin is contracted

MCAT Biology (7 decks)

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