Muscles and Skin Flashcards
what are myofilaments composed of and what are they used for
thick filaments myosin
thin filaments actin
muscle contraction
what are red fibres vs white in muscle
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
why does smooth muscle not appear striated
doesn’t contain sarcomeres
has loose myosin and actin for muscle contraction
uninucleate muscles vs multinucleate
uni - smooth muscle , cardiac (does have some multi)
multi - skeletal
how does cardiac muscle contract in sync
connected by intercalated discs with gap junctions
what determines the pace of heart rate
SA node
which muscles are striated
skeletal and cardiac
what do the sarcoplasmic reticulum do
store Ca in muscle cells
think of sacro like interior of muscle cell components
how does the sliding filament theory work
actin are attached to the z line and slide over myosin
what is the H zone
only myosin filament with no actin overlap
think H is a thick letter
what is the I band
only actin filaments with no myosin overlap
think I is a thin letter
what is the A band
the entire length of the myosin
what is the M line
the middle of the sarcomere where cross linking occurs
what happens to all the bands in muscle contraction
Z and M line gets closer to each other
H and I zones shrink
they all get smaller except A line stays the same
how does the cross bridge contraction work
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
why is calcium required for muscle contraction
to associate with troponin which moves tropomyosin out myosin binding sites on actin so myosin can bind
what causes release of Ca from the sarcoplasmic reticulum
Ach released from the NMJ of a motor neuron causes depolarization in the sarcolemma
what is similar between the epidermis and hair
they are far from the nutrient supply so the cells die and become keratinized
what type of cells are in the epidermis
melanocytes - pigment
langerhan - dendritic
merkel - mechanorecptors
what is contained in the dermis
how does this contribute to the function of skin
mechanoreceptors hair follicle blood sweat glands thermoregulation (piloerection)
what is in the hypodermis
how does this contribute to the function of skin
fat
macrophages
first line of defence, keeps us warm
order the layers of skin
epidermis
dermis
hypodermis
ligaments vs tendon
ligament connect bone to bone “like to like”
tendon muscle to bone
where can cartridge be found
joints nose ribs spine lungs
what is cartridge made of
chondrocytes which are cells that make up collagen
think of the face creams with collagen
firm but flexible
what type of joints are at the wrist
saddle and condyloid
synovial vs fibroid joint
synovial is freely movable not actually connected bone on bone
fibroid is stuck together like in the skull
what is hydroxyapatite
storage for calcium and phosphate in the bone
difference between osteoblast and osteoclast
clast break down bone when low blood Ca
blast build bone when blood ca high for storage
what does parathyroid hormone do
increase blood Ca
what is calcitriol
vit D analog that works to increase blood Ca through dietary absorption and osteoclast
what does calcitonin do
inhibit osteoclast and Ca absorption to decrease blood Ca
what is contained within compact bone
osteon which is a ring that the haversian canal is in the middle for blood and nerve supply
osteocytes in lacuna for communication
what is in spongy bone
bone marrow
blood vessels
what does red marrow do
produce red blood cells
what does yellow marrow do
storage for adipocytes
what happens if new ATP does not attach to a myosin head
the muscle remains contracted
what happens when someone is poisoned with an achetylcholinesterase inhibitor
paralysis
