1
Q
what is skeletal muscle
A
muscle which allow for movement and attached to bones (e.g. biceps and triceps)
2
Q
what is the role of tendons
A
attach skeletal muscle to bone
3
Q
what is the role of ligaments
A
attach bones to other bones
4
Q
how does skeletal muscle move
A
through contraction and relaxation which allows bones to move at joints
5
Q
what is a flexor
A
a muscle that contracts when it bends a joint (biceps bend elbow )
6
Q
what is an extensor
A
a muscle that relaxes when a joint straightens ( triceps straighten a joint)
7
Q
what is antagonistic pairs
A
muscles that work together to move a bone.
the two muscles create opposite forces to move the bone
as one muscle contracts and shortens the other relaxes and lengthens
8
Q
what is a muscle fibre
A
bundles of muscle cells
9
Q
what is the sarcolemma
A
the cell membrane of muscle cells
10
Q
what are transverse tubules
A
conduct electrical impulses (action potential) so they reach all parts of muscle
11
Q
label a muscle fibre
A
12
Q
what is the sarcoplasmic reticulum
A
network of internal membranes in the sarcoplasm that stores and releases calcium ions needed for muscle contraction
13
Q
what do muscle fibres have a lot of mitochondria
A
mitochondria provide ATP which is needed for muscle contraction
14
Q
what is the arrangement of muscle
A
muscle (organ), fascicles, muscle fibres, myofibrils, myofilaments (actin and myosin)
15
Q
what is the thick and thin filaments
A
actin - thin filament
myosin - thick filaments
16
Q
what are myofilaments made up of ?
A
actin and myosin (proteins)
17
Q
why is skeletal muscle striated
A
because of the I band (lighter band) and the A band (darker band)
18
Q
what is the A band
A
section of sarcomere where the myosin and actin overlap forming a darker band
19
Q
what is the I band
A
area where the myosin doesn’t overlap, there is only actin there making it lighter
20
Q
what is the m line
A
structure in the middle of the myosin that holds it in place
21
Q
what is the h zone
A
zone where there is only myosin the actin doesn’t cross over unless contraction is taking place
21
Q
what is the z line
A
the zigzag line that holds actin in place
22
Q
label a sarcomere
A
22
Q
what is a sarcomere
A
region between two Z lines
22
describes what happens to some zones during contraction of sarcomere
22
describe the sliding filament theory
1) Myosin heads are in high energy state, tropomyosin is covering the binging sites on the actin
2) excitation comes and synaptic transmission takes place - action potential is conducted through the transverse tubules
3) sarcoplasmic reticulum releases calciul ions
4) calcium ions bind to the troponin on the actin filaments this results in the exposure of the binding sites on actin filament. ATP on myosin head is hydrolised into ADP and pi
5) binding takes place between binding site of actin and myosin head (actin-myosin benign sites)
6)myosin heads pull on the actin resulting in contraction this is known as power stroke (myosin heads are in low energy state)
7) after contraction ATP provides energy to break the actin-myosin cross bridge so myosin heads detach form the actin filament ( back to high energy sate). ATP then hydrolised again.
8) myosin heads reattach to different binding sites further along the actin filament, a new actin myosin cross bridge is formed and cycle continues
8) as long as calcium is present and bound to troponin contraction will take place so after there is re-uptake of calcium ions into sarcoplasmic reticulum
23
what happens when excitation stops in sliding filament theory
when muscles stop being stimulates calcium ions leave their binding site on troponin and are moved by active transport back into sarcoplasmic reticulum
troponin molecule return to original shape
tropomyosin blocks binding sites again
myosin heads can't bind so no actin-myosin cross bridge, no contraction
actin filaments slide back to relaxed position which lengthens sarcomere
23
what are the two types of fibres skeletal muscle made up of (not actin/ myosin)
fats twitch and slow twitch fibres.
23
what is the role of slow twitch fibres ?
- contact slowly
- used for posture (back has higher proportion)
- good for endurance actives (long distance running)
- can work for long without getting tired
- energy released slowly through aerobic respiration (lots of mitochondria and blood vessels to supply muscles with o2)
- reddish in colour because rich in myoglobin (red coloured protein that stored o2)
23
what is the role of fast twitch fibres ?
-contract very quickly
-used for fast movement (in eyes and legs)
- good for short bursts of speed e.g. sprinting
-get tired quickly
- energy released quickly through anaerobic respiration using glycogen (stored glucose)
- fewer mitochondria and blood vessels
- whitish in colour because minimal myoglobin (can't store o2 )
24
Why is soda limes used in respirometer practical ?
-Soda limes absorb carbon dioxide
-So there will be a decrease in the volume of gas within the tube
-We can measure the rate of respiration
25
how could we work out the rate of respiration form a capillary tube?
identify the distance moved by the dye
find the area of the cylinder by
pie R squared x height (length) this will give us the area and then we can divide the area by time to give us the rate (volume of oxygen uptake cubed per minute)
26
What does a respirometer do ?
measures the volume of oxygen bing taken up, the more oxygen uptake the quicker the respiration
27
How may temperature influence the volume of gas in tube and how can we combat this
increase in temperature will increase the pressure of gas in tube as gases expand causing eye to move
lower temps cause gas to constrict causing dye to move
these will cause inaccuracies
we can connect control boiling tube to the respirometer containing beads the same volume as organisms. Any changes in temperature which change gas volume will cancel out.
28
state the respiration practical ?
boiling tubes contain same volume of soda lime
Add organisms into boiling tube on wire gauze
place in water bath and ensure clamps are open to allow free air flow
wait 10 minutes for organisms to acclimatise and respiration reaches a constant level
then measure the distance moved by the dye droplet over a given Time.
after that work out the rate by calculating area of distance dye moved divided by time .
29
what is cardiac output ?
volume of blood leaving the heart per minute
30
what is heart rate
number of heart beats per minute (BPM)
31
What is stroke volume ?
volume of blood pumped out of the hearts left ventricle per heartbeat
32
cardia output equation ?
cardiac output (cm 3/ min) = heart rate (bpm) x stroke volume (cm3)
33
factors influencing heart rate ?
Hormones
fitness level
age
34
factors affecting stroke volume ?
heart size
fitness level
gender
duration of contraction
35
describe the process of ventilation control
- inspiratory centre in medulla oblongata send nerve impulses to intercostal muscles and diaphragm to contract
- also sends impulses to inhibit actions of expiratory centre
- There is then an increase in lung volume which lowers pressure
- air enters lungs due to pressure difference between lungs and outside air
- as lungs inflate and stretch receptors in lungs stimulated
- nerve impulses are sent can to medulla oblongata which inhibit actions of inspiratory centre
- Expiratory centre no longer inhibited and send nerve impulses to cause intercostal muscles and diaphragm to relax
lungs deflate expelling air, stretch receptors become inactive, inspiratory centre no longer inhibited, cycle starts again
36
where is the ventilation centre
Medulla Oblongata
37
what are the who ventilation centres in the medulla oblongata
inspiratory centre
expiratory centre
38
label the intercostal muscles. diaphragm and medulla obligate ?
39
explain the effect of increased exercise on breathing rate ?
-more aerobic respiration
-more co2 production
-decrease in blood ph
-this picked up by chemoreceptors in medulla oblongata, carotid arteries and aortic arch
- chemoreceptors send nerve impulses back to medulla oblongata
- medulla sends more frequent nerve impulses to intercostal muscles and diagram
-causes rate and depth of breathing to increase
-there is an increase in gas exchange (more co2 out more o2 in)
40
what is the effect of exercise of heart rate
-increase in aerobic respiration
-increase in co2 production
-decrease in blood ph
- picked up by chemoreceptors in medulla, carotid artery and aortic arch
- medulla sends more frequent nerve impulse to SAN, nerve impulse then sent to AVN
- impulse travels down the bundle of his
-purkinje fibres cause ventricles to contract
- rate of heart contractions increase
-more venous return
-the more blood the more increase in force of contraction.
41
what is ventilation definition?
volume of air breathed in or our in a period of time e.g. minute
42
what is the purpose of the medulla oblongata ?
Contains the cardiovascular control centre (C.C.C) which controls heart rate.
controls rate at which SAN fires electrical impulses to cause atria to contract, as well as electrical impulses to AVN which cause ventricles to contract.
43
what are the pressure receptors and where are they
baroreceptors in the aortic ad carotid bodies - these are stimulated by high and low (changes) in blood pressure.
44
what are chemoreceptors and where are they ?
Chemoreceptors are receptors in the medulla oblongata, carotid artery and aortic arch. they monitor the Co2 levels of blood, PH levels of blood and Oxygen levels of blood.
45
what is the difference between the sympathetic nervous system and the parasympathetic nervous system ?
The sympathetic nervous system - gets body ready for action
- fight or flight system
- increases heart rate during exercise
Parasympathetic nervous system
- Calms the body down
-rest and digest system
-helps decrease heart rate after exercise
46
what effect does stimuli high blood pressure have on the heart rate
- High blood pressure is detected by baroreceptors.
- baroreceptors send nerve impulses c.c.c (Cardiovascular control centre).
-c.c.c sends impulses along parasympathetic neurones
-these secrete acetylcholine which binds to receptors on SAN
- SAN then fires less frequent impulses
- heart rate slows and reduces blood pressure back to normal
47
what affect does stimuli low blood pressure have on heart rate
low blood pressure detected by baroreceptors
- nerve impulses are sent to c.c.c
-nerve impulses sent along sympathetic neurones
-these secrete noradrenaline which binds to receptors on SAN
-SAN fires impulses more frequently to increase heart rate and blood pressure back to normal
48
what affect does stimulus high blood o2/ low co2/ high PH levels have on heart rate ?
-chemoreceptors detect these chemical changes in the blood
-nerve impulses sent to cardiovascular control center
- nerve impulses sent along parasympathetic neurones
-these secrete acetylcholine which binds to receptors on SAN
-The SAN fires impulses less frequently
- heart rate decreases, 02,C02, pH levels return back to normal
49
what effect does stimulus low blood 02/ High CO2/ Low pH have on heart rate
chemoreceptors detects this stimuli
-Nerve impulses sent to c.c.c
-nerve impulses sent along sympathetic neurones
-these secrete noradrenaline which binds to receptors on SAN
-SNA fires impulses more frequently
-heart rate increases
more gas exchange
-ph, 02, CO2 level back to normal
50
tidal volume definition ?
Volume of air in each breath
(usually o.4 cm cubed)
one breathe count as one inhalation + one exhalation
51
Breathing rate definition ?
how many breaths are taken up in a given time usually 1 minute
52
Oxygen consumption definition ?
volume of oxygen used by the body often expressed as rate (per minute)
53
Respiratory minute ventilation definition ?
Volume of gas breathed in or out in one one minute
54
how to calculate Respiratory minute ventilation ?
Respiratory minute ventilation = tidal volume x breathing rate
55
how to rearrange equation
remember to make the triangle!
56
label a lung graph diagram
57
inspiratory reserve volume definition ?
maximum volume of air a person can intake / breath in (inhale as much as can)
58
expiratory reserve volume definition ?
maximum volume of air a person can exhale
59
what is vital capacity ?
volume of air a person can exhale if they inhale as much as they can then exhale
60
the volume of carbo dioxide produced by aerobic respiration is the same volume of oxygen used by aerobic respiration.
61
why does the spirometer trace slope downwards ?
because the soda limes absorb co2 in the spirometer, the total of air in the spirometer decreases overtime this is why the spirometer trace slopes downwards
62
state the spirometer practical ?
-there is an oxygen filler chamber with moveable lid which contains soda limes.
- individual breathes through tube connected to chamber
- as person breathes in lid move down, breaths out, lid moves up
- these movements are recorded by a pen attached to lid of chamber which writes on rotating drum creating spirometer trace
total volume of gas decreases because of soda limes which absorb co2
63
how can a spirometer be used to measure the effects of exercise
-Person is breathing into a spirometer for one minute.
- Person then exercises for 2 minutes meanwhile spirometer becomes refilled.
- immediately after exercising the person goes back not spirometer for 1 minuter.
results are compared for before and after exercise
64
label/ have a look at spirometer mechanism
65
how do we find the breathing rate from a spirometer trace?
count the number of peaks in the trace in a minute
66
how do we identify tidal volume from a spirometer trace ?
find the average difference in the volume of gas between each peak and trough on the trace
67
how do we find oxygen consumption from a spirometer trace ?
find the change in the volume of gas in the spirometer
68
look at this data from a spirometer investigation which shows the effect of exercise on:
breathing rate
tidal volume
O2 consumption
respiratory minute ventilation.
69
look at the example where effect of fitness training programme is shown on a spirometer trace ?
70
homeostasis definition ?
Maintenance of the body's stable internal environment
71
why is homeostasis requires
thermoregulation -
keep temperature constant to stop enzymes being denatured or not active enough
- cells need constant energy supply so blood glucose concentration is carefully controlled. monitored by cells in the pancreas, blood glucose levels fall as more used up after exercise after respiration.
- water maintained at constant level by kidneys as loos water through waste secretion and sweat.
72
Definition of negative feedback
a change in a variable triggers a counteracting response. it is the negative feedback cycle that returns the body back to the correct internal conditions
73
positive feedback definition?
-Positive feedback mechanisms amplify a change form the normal level (this is not involved in homeostasis)
74
what is the process of the homeostatic system in homeostasis
the system contains receptors, communication systems and effectors.
A change in the body internal environment Is detected by receptors.
signal is communicated to the effectors via endocrine and nervous systems
the effectors bring about a response to counteract that change known as negative feedback .
body's internal conditions are then maintained e.g. body stays within +/- 0.5 of 37 degrees c
75
draw a negative feedback diagram ?
76
how does positive feedback mechanism work ?
some changes trigger positive feedback mechanism
this amplifies the change
effectors further increase the level away form normal level
it is useful to rapidly activate something e.g. blood clot after an injury
positive feedback can also happen when homeostatic systems break down e.g. hypothermia
positive feedback isn't involved in homeostasis as doesn't keep internal environment stable
77
Explain three ways in which the body is cooled down hen its too hot
1) Sweating: Sweat glands increase the production of sweat. More sweat to the surface of the skin. dues to skin being hot sweat evaporates. As sweat evaporates it takes heat energy from the body. The body is then cooled.
2) Hairs lie flat: hair traps air as insulation .
when its hot erector pili muscles relax . This results in laying flat on surface of skin. less air is trapped. Less insulation. Heat energy is lost more easily.
3) Vasodilation: Arteriols near surface of skin dilate.
this increases blood flow through capillaries at the surface layers of the epidermis/ skin. More that lost by radiation. Body temperature is lowered
78
explain 4 ways in which body temp is increased when it too cold?
1) Shivering: when its cold muscles contract is spasms.
-this causes shivering
- more heat is produced from increased respiration
2) Hairs stand up: erector pili muscles contract, hairs stand up, more air trapped, prevents heat loss
3) Vasoconstriction: arterioles near surface of skin constrict. less blood flows through capillaries in surface layer or epidermis. heat loss is reduced
4) Hormones: Body releases adrenaline and thyroxine. These increase metabolism and so more heat is produced.
79
how does thermoregulation work?
thermoreceptors detect a temperature that is too high.
Hypothalamus sends signal to effectors.
this causes visodilation, sweating, hairs lie flat, no shivering, no adrenaline or thyroxine released.
are heat is lost and less is produced by the body
return to normal body temp
when its too cold thermoreceptors detect this low temp
hypothalamus sends signal to effectors
vasoconstriction, ;less sweating, haircuts and upright, shivering, adrenaline and thyroxine
more heat is produced and conserved by the body
return to normal body temp
80
what is the difference between activators and repressors
activators increase the rate to transcription
repressors decrease the rate of transcription
81
how do hormones work as transcription factors for homeostasis ?
some hormones e.g. steroid hormones and thyroid hormones can cross the cell membrane, enter the nucleus and bind to transcription factors to alter gene expression.
others cannot e.g. protein hormones
82
how does thyroid hormone alter gene expression when it is too hot or too cold inside the cell ?
normal body temp thyroid hormone receptor (transcription factors) bind to DNA at start of gene.
-decrease in transcription of gene coding for protein that increases metabolic rate.
At cold temperatures thyroxine is released, this binds to thyroid hormone receptor causing it to act as activator.
the transcription rate of this gene coding for protein that increases metabolic rate increases.
the protein increases the metabolic rate causing and increase in the body temperature
83
what do hormones that connect entree the cell do as transcription factors?
some hormones (protein hormones aren't lipid soluble) cannot cross the cell membrane
they bind to receptors in the cell membrane which can activate messenger molecules in the cytoplasm
these molecules activate enzymes called protein kinases which trigger cascade inside the cell
during cascade transcription factors can be activated which affect transcription of genes in the cell nucleus
84
Biology A level mr Murphy
flashcards
Decks in class (10)
# Cards
-
life style health and risk (Topic 1, 1.1-1.11)26
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biology heart mistakes27
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Life style health and risk- topic 1, biological molecules 1.12-1.1821
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biological molecules past mistakes2
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Topic 4 Biodiversity and natural resources 4.7 - 4.13 so far35
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Biology calculations6
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PMT topic 10
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topic four redone !39
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topic 545
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topic 791
