Muscles and Skin

Question 1

what are myofilaments composed of and what are they used for

Answer 1

thick filaments myosin
thin filaments actin
muscle contraction

Question 2

what are red fibres vs white in muscle

Answer 2

red - slow twitch fibres that contain lots of myoglobin and mitochondria to make ATP through oxidative bc they have energy over long term
white - slow twitch fibres for quick short sprint relies on anaerobic metabolism and then lactic acid fermentation so less mitochondria and myoglobin

Question 3

why does smooth muscle not appear striated

Answer 3

doesn’t contain sarcomeres

has loose myosin and actin for muscle contraction

Question 4

uninucleate muscles vs multinucleate

Answer 4

uni - smooth muscle , cardiac (does have some multi)

multi - skeletal

Question 5

how does cardiac muscle contract in sync

Answer 5

connected by intercalated discs with gap junctions

Question 6

what determines the pace of heart rate

Answer 6

SA node

Question 7

which muscles are striated

Answer 7

skeletal and cardiac

Question 8

what do the sarcoplasmic reticulum do

Answer 8

store Ca in muscle cells

think of sacro like interior of muscle cell components

Question 9

how does the sliding filament theory work

Answer 9

actin are attached to the z line and slide over myosin

Question 10

what is the H zone

Answer 10

only myosin filament with no actin overlap

think H is a thick letter

Question 11

what is the I band

Answer 11

only actin filaments with no myosin overlap

think I is a thin letter

Question 12

what is the A band

Answer 12

the entire length of the myosin

Question 13

what is the M line

Answer 13

the middle of the sarcomere where cross linking occurs

Question 14

what happens to all the bands in muscle contraction

Answer 14

Z and M line gets closer to each other
H and I zones shrink
they all get smaller except A line stays the same

Question 15

how does the cross bridge contraction work

Answer 15

1 - ATP binds to myosin head causing conformational change and release of actin
2 - ATP hydrolyses to release energy and move myosin away from actin
3 - myosin binds actin upstream to pull the actin over myosin
4 - repeat

Question 16

why is calcium required for muscle contraction

Answer 16

to associate with troponin which moves tropomyosin out myosin binding sites on actin so myosin can bind

Question 17

what causes release of Ca from the sarcoplasmic reticulum

Answer 17

Ach released from the NMJ of a motor neuron causes depolarization in the sarcolemma

Question 18

what is similar between the epidermis and hair

Answer 18

they are far from the nutrient supply so the cells die and become keratinized

Question 19

what type of cells are in the epidermis

Answer 19

melanocytes - pigment
langerhan - dendritic
merkel - mechanorecptors

Question 20

what is contained in the dermis

how does this contribute to the function of skin

Answer 20

mechanoreceptors 
hair follicle
blood
sweat glands
thermoregulation (piloerection)

Question 21

what is in the hypodermis

how does this contribute to the function of skin

Answer 21

fat
macrophages
first line of defence, keeps us warm

Question 22

order the layers of skin

Answer 22

epidermis
dermis
hypodermis

Question 23

ligaments vs tendon

Answer 23

ligament connect bone to bone “like to like”

tendon muscle to bone

Question 24

where can cartridge be found

Answer 24

joints
nose
ribs
spine
lungs

Question 25

what is cartridge made of

Answer 25

chondrocytes which are cells that make up collagen think of the face creams with collagen firm but flexible

Question 26

what type of joints are at the wrist

Answer 26

saddle and condyloid

Question 27

synovial vs fibroid joint

Answer 27

synovial is freely movable not actually connected bone on bone fibroid is stuck together like in the skull

Question 28

what is hydroxyapatite

Answer 28

storage for calcium and phosphate in the bone

Question 29

difference between osteoblast and osteoclast

Answer 29

clast break down bone when low blood Ca | blast build bone when blood ca high for storage

Question 30

what does parathyroid hormone do

Answer 30

increase blood Ca

Question 31

what is calcitriol

Answer 31

vit D analog that works to increase blood Ca through dietary absorption and osteoclast

Question 32

what does calcitonin do

Answer 32

inhibit osteoclast and Ca absorption to decrease blood Ca

Question 33

what is contained within compact bone

Answer 33

osteon which is a ring that the haversian canal is in the middle for blood and nerve supply osteocytes in lacuna for communication

Question 34

what is in spongy bone

Answer 34

bone marrow | blood vessels

Question 35

what does red marrow do

Answer 35

produce red blood cells

Question 36

what does yellow marrow do

Answer 36

storage for adipocytes

Question 37

what happens if new ATP does not attach to a myosin head

Answer 37

the muscle remains contracted

Question 38

what happens when someone is poisoned with an achetylcholinesterase inhibitor

Answer 38

paralysis