Muscle Flashcards
Define bone
Strong and hard, made of bone cells which are fixed firmly in a matrix of collagen and calcium salts
Define cartilage
Tissue, hard but flexible sketetal tissue that often act as a shock absorber and prevent wear in joints
2 types of cartilage
Hyaline cartilage
- found at the end of the bones
White fibrous cartilage
Densely packed collagen in the matrix
—> great tensile strength but is less flexible
Define tendons
Inelastic white fibrous tissue made up of collagen fibre
MUSCLE TO BONE
Define ligament
Most elastic tissue which forms joint capsule
(JOINS BONE TOGETHER)
Define synovial fluid
Fluid which lubricates the most mobile joints
- act as a lubricant
- prevent wear and tear of the cartilage
Define Antagonistic pairs
Muscle work which work in opposition to each other pulling in opposite direction
Properties of smooth muscle
Involuntary control
Not striped under the microscope
—> muscle in the gut, blood vessel
Contract and fatigue slowly
Properties cardiac muscle
Only found in the heart
Involuntary control
Striated under the microscope (appears stripy)
The fibres are joined by special cross connection
Contract spontaneously
Doesnt get fatigue
Define sacromere
Basic unit of muscle structure
Define sarcoplasm
The cytoplasm of muscle cell
-contain many mitochondria
Function of sarcoplasmic reticulum
Endoplasmic recticulum found in sacromere
- stores and release calcium ion
Define myofibrils
A very long contracting fibre in skeletal muscle cells
Lying parallel to each other
Slow twitch is used for what activity
Maintain posture and during long periods of activity
What is fast twitch muscle used for
Rapid brief activity
Does slow twitch contain more myoglobin
Contains more myoglobin and rich blood supply
—> the extra myoglobin can release oxygen to enable continued aerobic respiration (release much more ATP)
Does fast twitch contain more or less myoglobin
Less myoglobin
Does slow twitch contain lots of mitochondria
More mitochondria
-maintain their activity without needing to respire anaerobically for any length of time
Does fast twitch contain lots of mitochondria
Less mitochondria and fewer blood vessels
-often perform anaerobic respiration
Slow twitch muscle fibre…
Which contracts and fatigues slowly
Fast twitch muscle fibre …
Contract very rapidly and strongly and fatigue quickly
Slow twitch contain less
Less glycogen stores
Less creatine phosphate
Fast twitch muscle fibre
Contains lots of rich glycogen stores which can be converted to glucose for both aerobic and anaerobic respiration
Contain high level of creatine phosphate which can be used to convert ATP to ADP
Through training the muscle what changes
The number of muscle fibre doesn’t change but the size and type of fibre can change
What is actin made up of
Made up of two chain of actin monomers joined together like a beads of necklace
What does the actin do
Troponin: protein molecules attached to tropomyosin changes shape due to the binding of calcium ions leading to a conformational shape change
Pulling in the tropomyosin and revealing the myosin binding site on the actin strands
In relaxed state tropomyosin covers the myosin binding site
What’s myosin made up of
Two long polypeptide chains twisted together
Sliding filament theory
When action potential reaches a muscle causes a response from impulse down motor neurone to neuromuscular junction
Causing the sarcoplasmic reticulum to release calcium ions
Calcium ions bind to the binding site causing a conformational change
Troponin moves and pulls the attached tropomyosin exposing the myosin binding site on the actin strand
Myosin head binds to myosin binding site on actin forming a cross bridge
Myosin head binds to actin; myosin changes shape by bends forward moving the actin : ADP+ Pi released from myosin head
Free ATP bind to the head causing another shape change in the myosin so the binding of the head to the actin strand is broken
Activating ATPase in the myosin head, which also needs calcium ions to work
ATP is hydrolysis providing the energy to return the myosin head to its original position with ADP and Pi
Myosin head move back to the original position and cycle repeats
Sarcoplasmic recticulum sucks all calcium ion back up calcium pumped back via active transport
Describe the role of calcium ions in the contraction of skeletal muscle
1) calcium ions released in response to nervous stimulation of the muscle set up contreaction of sacromere
2)calcium ion binds to troponin changing the shape of the molecules
-this changes the shape of troponin so the pull the tropomyosin this moves the tropomyosin away from the myosin binding site with the myosin head
3) calcium ions is needed for action of ATPase enzyme in the myosin heads, which enables the heads to return to their resting position
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How is the heartbeat controlled
1) the sinoatrial node established a wave of electrical excitation (depolarization) which causes the atria to starting contracting. This initiate the heartbeat
2) excitation also spreads to another area AVN (atrioventricular node)
3)the AVN is excited as result of the SAN but it produces a slight delay before the wave of depolarization passes into the BUNDLE OF HIS(this make sure that the atria stop contracting before the ventricle starts)
4) the bundle of his into two branches and carries the wave of excitation on into the purkyne tissue
5) the purkyne tissue consist of conducting fibre that penetrate down the septum, spreading around the ventricle
6) as depolarization travels through the tissue it starts the contraction of the ventricles starting at the bottom and so squeezing blood out of the heart
Formula for cardiac output
Cardiac volume x heart rate
What does the sympathetic nervous system do
Excitatory
— noradrenaline will be used as the neurotransmitters—> to stimulate SAn
What does the parasympathetic system do to the heart
Inhibitory
— acetylcholine will be used as neurotransmitters—> to inhibits SAN
What is the role of baroreceptor and where is it found
Aortic and carotid bodies
They are stimulated by changes in blood pressure
What does the baroreceptor have in common with control of heart rate when adrenaline is released
1) adrenaline causes the blood vessel dilate (vasodilation) thus causing the blood pressure to reduce
2) causing a reduction of stimulation of baroreceptor
3) cardiovascular control centre sends the impulse along the sympathetic nervous system to stimulate heart
4) this increases the heart rate and blood pressure again by constricting the blood vessel
What does the baroreceptor have in common with control of heart rate when exercise stop
1) when excerise stops, blood pressure in the arteries increases as the heart continues to pump harder
2) the baroreceptor is stimulated and stretched
3) sending more sensory nerve impulses through the control centre which send impulses through the parasympathetic system to slow down the heart rate and blood vessel to be wider
What does chemoreceptors found and what is it stimulated by
Found in medulla oblongata and aortic and carotid bodies
Stimulated by levels of carbon dioxide and oxygen and blood pH
Process of high blood pressure
Detected by baroreceptor which send impulse to cardiovascular control centre
It sends impulse along the sympathetic neurone which secrete the neurotransmitters noradrenaline
—> noradrenaline binds to receptor on SAN causing it to fire more frequently
Heart rate slow down and blood pressure decrease back to normal
Process of high O2/Low CO2/high pH levels
Detected by chemoreceptors which sends to cardiovascular control centre
It sends impulses along the parasympathetic neurones which secrete the neurotransmitters acetylcholine
-acetylcholine bind to receptor on SAN causing it to fire less frequently
Heart rate slow down and O2 and pH level return to normal
When there is an increases in carbon dioxide in the blood
1) carbon dioxide levels goes up this decreases the pH level
2) detected by the carotid and aortic chemoreceptors
3) they send impulses along sensory neurone to the cardiovascular control centre in the oblongata
4) thus, increase the number of impulses travelling down the sympathetic nerve to the heart
5)this result in an increased heart rate, increasing the blood flow to the lungs and so more carbon dioxide is removed from the blood
What happens when carbon dioxide level Low in the blood
1) carbon dioxide level is Low and the blood pH increases
2) this is detected by carotid and aortic chemoreceptors
3)the chemoreceptors respond by reducing the number of impulse send to the cardiovascular control center
4) this then reduces the number of impulses along the parasympathetic nervous system
5) decreases the heart rate
6)decreased the blood flow to the lungs
Where is adrenaline released from
Adrenal medulla when in fight or flight mode
Process of adrenaline
1) adrenaline is transported around the body in the blood stream
2) it will bind to receptor on the target organ (example:SAN)
3)increase the frequency of excitation
4)increase the heart rate to supply blood to the muscle cell at a faster rate
5) more blood more oxygen and glucose that reaches the muscle cell which in turn increases the rate of aerobic respiration
6) this releases mor energy that will be used during the response to the stressful or dangerous situation
4)
How does adrenaline affect the cardiovascular control centre
Stimulate the cardiovascular control centre in the medulla oblongata
This increases the impulse travelling along the sympathetic neurones affecting the heart furthering speeding up the heart rate
