Topic 7 Flashcards
what type of muscle is used for movement?
skeletal, e.g. biceps and triceps
what do ligaments attach?
bones to bones
what do tendons attach?
muscles to bones
what is a flexor?
a muscle that contracts to bend a joint
what is an extensor?
a muscle that contracts to cause the extension of a joint
which muscle in on the top of the arm? is it an extensor or flexor?
biceps- flexor
which muscle is on the bottom of the arm? is it an extensor or flexor?
triceps- extensor
what is a pair of muscles that work together to move a bone called?
an antagonistic pair
why do muscles need to work in pairs?
they can only pull (when they contract) and not push, so two muscles of opposite directions are needed to create opposite forces
what are skeletal muscles made of?
large bundles of long cells called muscle fibres
what is the cell membrane of a muscle fibre cell called?
sarcolemma
what is the sarcolemma?
the cell membrane of a muscle fibre cell
what is the cytoplasm of muscle fibre cells called?
sarcoplasm
what are transverse T tubules?
inward folds of the sarcolemma which stick into the sarcoplasm
what is the function of the transverse T tubules?
help to spread electrical impulses throughout the sarcoplasm so they reach all parts of the muscle fibre
what is the sarcoplasmic reticulum?
a network of internal membranes that run through the sarcoplasm in a muscle fibre cell
what is the function of the sarcoplasm reticulum?
stores and releases calcium ions that are needed for muscle contraction
why do muscle fibre cells have lots of mitochondria?
to provide the ATP that’s needed for muscle contraction
which type of cell are multinucleate? what does this mean?
muscle fibre cells- have many nuclei
what are muscle fibres made of?
long, cylindrical organelles called myofibrils
how is a muscle fibre cell related to its specialised function?
many mitochondria for respiration
presence of myofibrils/ actin and myosin
myofibrils allow for contraction
what are myofibrils made of?
proteins
what are myofibrils highly specialised for?
contraction
what are myofibrils made of?
bundles of thick or thin myofilaments that move past each other to make muscles contract
what are thick myofilaments made of?
the protein myosin
what are thin myofilaments made of?
the protein actin
what does myofibril look like under a microscope?
has alternating dark and light bands
what is a sarcomere?
a section of myofibril
what are the dark bands in myofibril?
the thick myosin filaments and some overlapping thin actin filaments (A bands)
what are in A bands?
mostly thick myosin filaments which the ends overlapping with thin actin filaments
what are the light bands in myofibril?
thin actin filaments (I bands)
what are in I bands?
thin actin filaments
what is a sarcomere?
the short units which make up myofibril
what are Z lines?
they mark the end of each sarcomere, sarcomeres are joined lengthways at their Z lines
what is the M line?
marks the Middle of the sarcomere, is always in the Middle of the Myosin filament
what is the H zone?
the zones in the middle of the sarcomere- only contains myosin filaments
what is the theory which explains muscle contraction?
sliding filament theory
what fundamentally happens during contraction?
actin and myosin filaments slide over each other to shorten the sarcomere
during muscle contraction which zones/bands shorten and which stay the same length?
H-zone and I-band shorten
A bands stay the same length
what 3 things shorten during contraction?
sarcomeres, myofibrils and muscle fibres
what are the 9 features of the knee?
tendon, muscle, ligament, synovial membrane, synovial fluid, fibrous capsule, bone, pad of cartilage, cartilage
what is the function of the synovial membrane?
secretes synovial fluid
what is the function of the synovial fluid?
acts as a lubricant
what is the function of the pad of cartilage?
gives additional protection
what is the function of cartilage?
absorbs synovial fluid, acts as shock of absorber
what is the function of the fibrous capsule?
encloses joints
define tropomyosin
an actin-binding protein which regulates muscle contraction
define troponin
a complex of three proteins, attached to tropomyosin
what is the resting state of a muscle?
tropomyosin blocks binding site on actin
what is the first step of muscle contraction?
action potential reaches neuromuscular junction and depolarises sarcolemma and sarcoplasmic reticulum
what happens after the sarcoplasmic reticulum is depolarised?
sarcoplasmic reticulum releases calcium ions which bind to troponin
what happens when the calcium ions bind to troponin?
troponin changes shape which causes tropomyosin to move so the myosin binding sites (on the actin) are exposed
what happens once the myosin binding sites are exposed?
the myosin heads can bind to binding site on actin
actin-myosin cross bridge forms
what happens after the actin-myosin cross bridge forms?
the myosin head nods forward causing the actin filaments to slide over the myosin filaments and the sarcomere shortens
what happens after the sarcomere shortens?
ATPase in myosin head hydrolyses ATP and head moves back to original position- breaking cross bridge
what is the final stage of muscle contraction?
myosin head reattaches to a different binding site further along the actin filament
what is the equation for respiration?
glucose+oxygen -> carbon dioxide + water
what is the overall explanation for aerobic respiration?
the splitting of glucose to release carbon dioxide as a waste product, and reuniting hydrogen with oxygen with the release of a large amount of energy
what are the 2 types of respiration?
aerobic and anaerobic
what are the stages in aerobic respiration?
glycolysis, link reaction, Krebs cycle, oxidative phosphorylation
where does the link reaction occur?
the matrix of the mitochondria
where does glycolysis occur?
the cytoplasm
where does the Krebs cycle occur?
the matrix of the mitochondria
where does oxidative phosphorylation occur?
between the matrix and the inter-membrane space
how many ATP are made in aerobic respiration?
38 total ATP
what is involved in glycolysis?
the splitting of glucose
what are the 2 stages of glycolysis?
phosphorylation and oxidation
what is produced in glycolysis?
2x pyruvate, 2x ATP (net gain), 2x NADH
what 2 things are needed for the link reaction?
pyruvate and co enzyme A
what is produced in the link reaction? (per pyruvate not per glucose)
carbon dioxide, acetyl coA, and NADH
what is needed for the Krebs cycle?
acetyl coA
what is produced by the Krebs cycle? (per cycle not per glucose)
2x carbon dioxide, 3x NADH, FADH, ATP
where do the H atoms come from in oxidative phosphorylation?
they are released as the coenzymes are oxidised
where do the electrons go in oxidative phosphorylation?
move down ETC
where do the H+ ions get pumped in oxidative phosphorylation?
from the matrix into the inter-membrane space of the mitochondrion
what process occurs during oxidative phosphorylation?
chemiosmosis
what is the final electron acceptor in oxidative phosphorylation (aerobic respiration)?
oxygen
what is the final product of oxidative phosphorylation?
water
what are the stages of anaerobic respiration?
glycolysis and lactate fermentation
does aerobic respiration need oxygen?
yes
does anaerobic respiration need oxygen?
no
what is needed for lactate fermentation?
pyruvate and NADH
what is made in lactate fermentation?
lactate/ lactic acid
what is the issue with lactate?
accumulates in cytoplasm of cells, decreases pH, neutralises negatively charged groups on the active sites of enzymes, affects binding and activity of enzymes
what can lactate be converted into in lactate fermentation?
cells can convert into pyruvate and liver cells can convert into glucose
why can anaerobic respiration continue?
because the NAD needed for glycolysis is produced in lactate fermentation from the NADH produced in glycolysis
what happens after anaerobic respiration?
most lactate converted back to pyruvate, this takes lots of oxygen, some lactate converted to glucose and forms glycogen in liver or muscles
why can aerobic respiration not happen with no oxygen?
no oxygen to accept electrons from ETC, coenzymes not oxidised, NAD not regenerated, no NAD for Krebs cycle or link reaction
why do fast twitch fibres contain more glycogen than slow twitch?
fewer capillaries in fast twitch so less glucose supplied, more glucose needs to be supplied by a store
which type of muscle fibre uses aerobic respiration?
slow twitch
which type of muscle fibre uses anaerobic respiration?
fast twitch
which type of muscle fibre has lots of miochondria?
slow twitch
which type of muscle fibre has few mitochondria?
fast twitch
which type of muscle fibre contract quickly?
fast twitch
which type of muscle fibre contract slowly?
slow twitch
which type of muscle fibre is tired more quickly?
fast twitch
where are slow twitch muscle fibres found?
in back and posture muscles
where are fast twitch muscle fibres found?
in eye and leg muscles
what activities are fast twitch fibres adapted for?
short bursts of speed and power- sprint
what activities are slow twitch fibres adapted for?
endurance activities- marathon
which type of muscle fibre has high blood supply?
slow twitch fibres
what colour are fast twitch muscle fibres?why?
white as low levels of myoglobin (protein which stores oxygen)
what colour are slow twitch muscle fibres? why?
red as rich in myoglobin (protein which stores oxygen)
why does rate of aerobic respiration increase during exercise?
your muscles contract more frequently which means they require more energy
how does the body respond to exercise?
breathing rate and depth increase to obtain more oxygen and remove more carbon dioxide
heart rate increases to increase rate of blood flow to deliver oxygen and remove carbon dioxide from respiring muscle cells
what controls breathing rate?
the medulla oblongata contains two ventilation centres
what are the 2 ventilation centres in the medulla oblongata?
the inspiratory centre and the expiratory centre
how does inhalation occur?
the inspiratory centre sends impulses to the external intercostal and diaphragm muscles to make them contract and to inhibit the expiratory centre
this increases volume and decreases pressure in the lungs
air enters the lungs due to pressure in the lungs being lower than in the air
this stimulates stretch receptors
how does expiration occur?
the stimulated stretch receptors send nerve impulses to the medulla oblongata which inhibits the inspiratory centre
the expiratory centre (no longer inhibited) sends impulses to relax the diagram and intercostal muscles
lungs deflate and expel air
stretch receptors become inactive and inspiratory centre in no longer inhibited (cycle starts again)
what type of receptor detects changes in blood pH?
chemoreceptors
why does the pH of the blood decrease during exercise?
carbon dioxide dissolves in the blood plasma and forms carbonic acid which dissociates into hydrogen and hydrogen carbonate ions
what happens after the chemoreceptors detect a decrease in pH?
impulse sent to medulla oblongata which sends more frequent impulses to the intercostal muscles and diagram. increasing depth and rate of breathing
where are chemoreceptors found?
in the medulla oblongata, aorta, and carotid arteries
what are baroreceptors?
detect change in blood pressure and found in aorta and carotid arteries
how is heart rate increased due to low blood pressure or low pH?
baroreceptors detect low bp or chemoreceptors detect low pH, send impulses to the cardiovascular control centre, control centre sends impulses along sympathetic neurones which secrete the neurotransmitter noradrenaline, noradrenaline binds to receptors on the SAN causing it to fire more frequently, heart rate increases
what neurone pathway is used to increase heart rate and which neurotransmitter is used?
sympathetic pathway uses noradrenaline
how is heart rate decreased due to high blood pressure or high pH?
baroreceptors detect high bp or chemoreceptors detect high pH, send impulses to cardiovascular control centre, control center sends impulses along parasympathetic neurones which secrete the neurotransmitter acetylcholine, acetylcholine binds to receptors on the SAN causing it to fire less frequently, heart rate slows
what neurone pathway is used to slow heart rate and which neurotransmitter is used?
parasympathetic pathway uses acetylcholine
define minute ventilation
the amount of air that enters the lungs per minute
define inspiration
the process of taking in oxygen rich air
define expiration
the process of expelling air from the lungs
define spirometer
an apparatus for measuring the volume of air inspired and expired by the lungs
define residual volume
the small amount of air always retained in the lungs
define breathing rate
the number of breaths in one minute
define tidal volume
the amount of air that moves in or out during inspiration or expiration
define oxygen consumption
the amount of oxygen taken in, in one minute
define vital capacity
the maximum air which can be exhaled from the lungs
define total lung capacity
the maximum amount of air the lungs can hold (including residual air)
how do you find respiratory minute ventilation from a spirometer trace?
find tidal volume (difference between a peak and a trough)
find ventilation rate (number of breaths in one minute)
multiply together
how do you find oxygen consumption per minute from a spirometer trace?
find gradient of bottom of peaks
divide by time and multiply by 60
what has to be considered when selecting candidates for spirometry?
whether the candidate is healthy or meets criteria (age, health, gender)
what 3 points have to be included in a spirometry method?
soda lime to absorb carbon dioxide for health reasons
nose clip to ensure all air exhaled and inhaled goes through the spirometer
equipment sterilised between candidates to prevent spread of bacteria/viruses
what are the symptoms of altitude sickness?
breathing rate increases, headaches, blue lips, dizziness, feeling faint, hyperventilation, hypoventilation
why does altitude sickness occur?
as altitude increases, oxygen levels decrease
what are the 5 warming mechanisms?
vasoconstriction, boosting metabolic rate, shivering, hairs, less sweating
how does vasoconstriction increase body temp?
in the arterioles near the skin, the walls constrict minimising the heat radiated to the surroundings, blood passes further under the skin
how does boosting metabolic rate increase body temp?
most metabolic reactions are exothermic and so give out energy. thyroxine and adrenaline increase metabolic reactions
how does shivering increase body temp?
the muscles are effectors which rapidly contract providing heat
how do hairs increase body temp?
the erector pili muscles contract- causing hairs to stand, this forms an insulating layer of air around the skin
how does less sweating increase body temp?
sweat glands produce less sweat, less heat lost through evaporation
what are the 3 cooling mechanisms?
vasodilation, sweating, flattening of hairs
how does vasodilation decrease body temp?
arterioles near the skin dilate, increasing the amount of heat radiated to the surroundings
how does sweating decrease body temp?
this cools the skin via evaporation, as energy is lost with the water as it turns from liquid to a gas
how does the flattening of hairs decrease body temp?
the erector muscles in the skin relax, muscles act as effectors, stops hairs forming a layer of insulation
what is hyperthermic?
37 + (too hot)
what is hypothermic?
less than 37 (too cold)
why is hyperthermia worse than hypothermia?
hypothermia- the enzymes slow down due to lack of energy (could be recoverable)
hyperthermia- enzymes denature- not recoverable
which tissue is myogenic?
cardiac muscle
define myogenic
can beat without external stimulus
what is the normal heart rate?
60bpm
what is the SAN?
sinoatrial node- a group of cells in the wall of the right atrium which generates electrical impulses
where is the non-conducting tissue in the heart?
between the bottom of the atria, and the top of the ventricles
why is there a slight delay in the conduction of the heart?
the impulse cannot directly pass from the atria to the ventricles due to non-conducting tissue
what does the delay in the conduction of the heart allow?
time for the atria to complete contraction and the ventricles to fill with blood
what is the AVN?
atrioventricular node- a region of conducting tissue between the right atrium and right ventricle
where is the bundle of His and what is it made of?
in the septum of the heart, purkyne fibres
where do the ventricles contract from?
the apex/ bottom of the heart upwards
what are the 4 features of an electrocardiogram?
P wave, QRS complex, T wave, U wave
what causes the P wave on an ECG?
depolarisation of the atria
what causes the QRS complex on an ECG?
the depolarisation of the ventricles
why is the QRS complex the largest on an ECG?
ventricles have the largest muscles mass and so greater amount of electricity needed to depolarise
what causes the T wave on an ECG?
the repolarisation of the ventricles
what causes the U wave on an ECG?
scientists are unsure but may be the repolarisation of the Purkyne fibres
why is the repolarisation of the atria not shown on an ECG?
it occurs at the same time as the depolarisation of the ventricles and is smaller than the QRS complex
what is tachycardia?
when the heart beats too fast- resting heart rate 100+ bmp
what is bradycardia?
when the heart beats too slow- resting heart rate less then 60bpm
what is arrhythmia?
when the heart beats irregularly
define cardiac output
the volume of blood that is pumped by the heart (left and right ventricles) in one min (cm cubed per min)
define stroke volume
the volume of blood pumped out of the left ventricle during one cardiac cycle (cm cubed)
what is the equation for cardiac output?
cardiac output= heart rate x stroke volume
what are the 5 impacts of lots of exercise?
suppression of immune system
healthy weight maintenance
reduced blood pressure
improves wellbeing
wear and tear on joints
what are the 2 disadvantages of too much exercise?
suppression of immune system
wear and tear on joints
what are the 4 reasons why athletes have a higher risk of upper respiratory track infections?
lots of people in close proximity
travel- more likely to come into contact with pathogens
more cortisol and adrenaline which reduces inflammatory response and antibody production
lowers activity and production of T killer cells
how does too much exercise suppress the immune system?
higher levels of cortisol and adrenaline which reduces inflammatory response and antibody production
lowers activity and production of ‘natural’ killer cells
what are the effects of doing too little exercise?
increased risk of obesity, cardiovascular disease and diabetes (type 2)
where are thermoreceptors found?
in the hypothalamus
what are the 8 features of the endocrine system?
testes, ovaries, pancreas, adrenal gland, parathyroid, thyroid gland, pituitary gland, hypothalamus
what is the role of the pancreas?
regulates blood sugar by secreting insulin and glucagon
what is the role of the adrenal gland?
help to trigger the fight or flight response by secreting adrenaline and cortisol
what is the role of the testes?
secretes male sex hormones (testosterone)
what is the role of the ovaries?
secretes female sex hormones (oestrogen and progesterone)
what is the role of the parathyroid?
to help regulate the level of calcium in the blood
what is the role of the thyroid gland?
regulates metabolism by secreting thyroxine
what is the role of the pituitary gland?
secretes many hormones including LH and FSH
what is the role of the hypothalamus?
contains thermoregulatory centre
what are the 2 types of hormone?
peptide and steroid
which type of hormone cannot cross the cell membrane?- why?
peptide- due to lack of charge
how do hormones which can cross the cell membrane cause an effect?
hormones enter cell, enter nucleus, bind to transcription factors
how do hormones which cannot cross the cell membrane cause an effect?
bind to receptors on the membrane, activates second messengers in the cytoplasm, these molecules activate enzymes called protein kinases, causes a cascade of reactions, cascade results in change in activity of transcription factors affecting gene expression
give an example of a hormone which can cross the cell membrane
thyroxine- regulates body temperature by changing metabolic rate
what is a transcription factor?
a protein that controls the transcription of genes by binding to a specific region of DNA
what are the 2 types of transcription factors? and what do they do?
activators (increases rate at which gene is expressed) and repressors (decrease gene expression)
what 2 things do transcription factors allow?
allow organisms to respond to their environment, ensure the correct genes are being expressed in the correct cells at the correct time
what is doping?
using drugs to enhance performance
what is the WADA?
world anti-doping agency
what is the advantage of blood doping?
more blood, more haemoglobin, more oxygen transportation
what is the advantage of human growth hormone?
increase of muscle mass and bone density
what is the advantage of insulin?
increases blood glucose levels for more respiration
what is an exocrine gland?
secretes hormones into a duct not directly into the blood
what is an endocrine gland?
secrets hormones directly into the blood
why don’t all hormones effect every cell?
hormones only affect the target organs with the target cells which have the target receptors (so localised effect caused)
what are the stages of treatment for a joint injury?
- RICE (rest, ice, compress, elevate) and take anti-inflammatory painkillers (ibuprofen)
- surgical repair
what are the benefits of key-hole surgery?
lower risk of infection, shorter recovery time, shorter stay in hospital, less invasive, less blood loss,
what is a prosthesis?
an artificial version of a missing body part
what are some of the ways prostheses can be adapted to their uses?
may have rough surface on the bottom of a prosthetic foot to provide friction/grip for rock climbers, a plastic spacer can be placed between the metal pieces of a knee joint to provide cushioning and reduce the impact on the knee for people in sports
what are the 2 types of prosthesis?
articulated (with joints) or non-articulated (no joints/only knee)
what is the mechanism used to maintain homeostasis?
negative control
what is the effect of a negative feedback system?
reverses a change and brings the body back to normal limits
what 3 things are included in a negative feedback loop?
a receptor which detects a change/ stimulus
a coordination system to transfer information to different parts of the body (hormonal or nervous)
an effector which carries out a response (muscles or glands)
what is the effect of a positive feedback system?
enhances the effect of the original stimulus
give an example of a positive feedback loop
dilation of the cervix during labour-
cervix stretches, stretch receptors stimulated and send impulses to the brain, pituitary gland produces oxytocin which increases intensity of uterine contraction, pushes baby further down birth canal and stretches cervix further.
Give 3 performance enhancing drugs
Erythropoietin (EPO), testosterone, anabolic steroids
describe Erythropoietin
peptide hormone
made by kidneys
stimulates bone marrow to make new red blood cells
difficult to test if high levels are natural or not
risk of blood clotting exasperated by dehydration
binds to receptors in bone marrow, altering gene expression involved in haemoglobin formation
describe testosterone
steroid hormone
made from cholesterol
risks of high blood pressure, liver damage, kidney failure and heart disease
what are the 2 ways of detecting illegal performance enhancing drugs?
mass spectrometry
testosterone: epitestosterone ratio above 4:1
what is the absolutists view on performance enhancing drugs?
no drugs for improving performance should be allowed in sport and so maximum red cell count testing/ guidelines is not adequate as it allows for the use of drugs
what is the relativists view on performance enhancing drugs?
setting a maximum level for total red blood cell count is the only fair way to make sure that nobody is tempted to add to their natural count to a point where they may damage their bodies using either high-altitude training (legal) or EPO (illegal)
