Chapter 7: SNAB biology Flashcards
7.10 i) Know the structure of a muscle fibre.
7.1 The way in which muscles, tendons, skeleton and ligaments interact
Muscles bring about movement at a…
joint.
7.1 The way in which muscles, tendons, skeleton and ligaments interact
What are a pair of muscles that work together called?
Antagonistic muscle pair
Why do you need antagonist muscle pairs?
Muscles can only pull if they cant push, so at least two muscles are required to allow movement for a bone
7.1 The way in which muscles, tendons, skeleton and ligaments interact
What is an extensor muscle?
A muscles that contracts to cause an extension of a joint.
7.1 The way in which muscles, tendons, skeleton and ligaments interact
What is a flexor muscle?
A muscle that contracts to reverse the movement of an extensor muscle.
7.1 The way in which muscles, tendons, skeleton and ligaments interact
What is a synovial joint and examples of it?
Holding bones that move freely as they are separated by a cavity filled with sinovial fluid
7.1 The way in which muscles, tendons, skeleton and ligaments interact
Bones are held in position by (a) that (b)
a-ligaments
b-control and restrict the amount of movement in the joint
7.1 The way in which muscles, tendons, skeleton and ligaments interact
What are tendons?
Attachers of muscles to bones enabling the muscle to power joint movement
7.1 The way in which muscles, tendons, skeleton and ligaments interact
What is cartillage?
Protects bones within joints
7.1 The way in which muscles, tendons, skeleton and ligaments interact
Other than the sinovial joint what are other types of joints in humans
Ball and Socket-round head fits into a cup shaped socket (allows movement in many directions
Gliding-two flat surfaces slide over one another
Hinge-convex surface fits into concave surface (two direction movement)
Pivot-Part of one bone fits into a ring shaped structure allowing rotation
7.10 i) Know the structure of a muscle fibre
What is a muscle made up of?
Muscle Fibres each of which is one cell
7.10 i) Know the structure of a muscle fibre
Within each muscle fibre what is the next smallest thing?
Numerous myofibrils
7.10 i) Know the structure of a muscle fibre
What is a myofibril made up of?
Sarcomeres
7.10 i) Know the structure of a muscle fibre
What two types of protein molecules is a sarcomere made of? (which is thin and which is thick)
thin filament-actin
thicker filament-myosin
7.10 i) Know the structure of a muscle fibre
How are the filaments arranged in the sarcomere?
Proteins overlap and give the muscle fibre striped appear. Lighter band-actin, Dark band- both myosin and actin. Just myosin-intermediate coloured band
7.10 i) Know the structure of a muscle fibre
How does the sarcomere shorten?
Sliding filament theory
7.10 i) Know the structure of a muscle fibre
What allows the mysoin to attach to the actin and move along it?
Heads protuding along the myosin’s length attach to the actin and by the change of orientation of the myosin head, they dip forward sliding actin over the myosin.
7.10 i) Know the structure of a muscle fibre
What are the two protein molecules that actin is associated with?
Troponin and Tropomysoin
7.10 i) Know the structure of a muscle fibre
What triggers the movement of protein filaments in the sliding filament theory?
- Nerve impulse arrives at neuromuscular junction
- Ca2+ are released from the sarcoplasmic reticulum (system of membrane bound sacs around myofibrils)
- Ca2+ diffuses through the sarcoplasm (cytoplasm)
- Initated movements of protein filaments
7.10 i) Know the structure of a muscle fibre
Protein Filament movement process (Sliding Filament Theory)
- Ca2+ attaches to troponin molecule allowing it to move
- Tropomysoin on actin filament shifts its position exposing myosin binding sites on actin filaments
- Myosin heads bind with myosin binding sites on actin filament forming cross bridges
- Myosin head binds to the actin and ADP and Pi on myosin head are released
- Myosin changes shape causing the head to nod forward, movements results in movement of filaments and attached actin moves over myosin
- ATP molecule binds to the myosin head causing myosin head to detach from actin
7.ATPase on myosin head hydrolyses the ATP forming ADP and Pi
8.Hydrolysis causes change in shape of myosin head,** returning to its upright position**
7.10 i) Know the structure of a muscle fibre
What happens to muscle when it relaxes?
As it is no longer stimulated by nerve impulse, Ca+ Ionsa are actively pumped out of the sarcoplasm using ATP. Troponin and Tropomyosin move back, once again blocing myosin binding sites on actin.
7.10 differences between fast and slow twitch muscle fibres
What is a slow twitch muscle fibre?
Few mitochondria - High creatine phosphate - High glycogen - few capillaries - lighter in color
Adapted to fast release of energy
7.10 differences between fast and slow twitch muscle fibres.
What is a slow twitch muscle fibre?
Many mitochondria - high myoglobin - low creatine phosphate - low glycogen - darker in color
Adapted to slow prolonged release of energy
7.3 i) Understand the overall reaction of aerobic respiration
What is aerobic respiration?
Releasing large amounds of energy and CO2 as a waste product by uniting hydrogen with a split respiratory substrate
7.3 i) Understand the overall reaction of aerobic respiration
Overall respiration reaction
C6H12O6 + 6O2 -> 6CO2 + 6H2O
7.3 i) Understand the overall reaction of aerobic respiration
Respiration is a () many stepped process and each step is ()
Respiration is a metabolic pathway: many stepped process - each step is enzyme controlled/catalyzed
7.3 i) Understand the overall reaction of aerobic respiration
What is ATP made of?
ATP is created by ADP and inorganic phospate. In solution phosphate ions are hydrated.
7.3 i) Understand the overall reaction of aerobic respiration
Where does glycolysis occur?
The cytoplasm
7.4 Understand the roles of glycolysis
What does Glycolysis form as products?
2 ATP (net gain)
2 pyruvate (3C)
2 NADH & H+
7.4 Understand the roles of glycolysis
Outline the process of glycolysis
- Hexose Sugar is Phosphorylated (Fructose bisphosphate 1,6) splits down middle into G3P 2x (two trios phosphate)
- This G3P is oxidized by NAD
- NAD gets reduced to NADH
- As this redox occurs this provides the energy to convert 4ADP + Pi to 4ATP
- 4 ATP produced resulting in 2 ATP net gain
- 2 pyruvate molecules are produced
7.4 Understand the roles of glycolysis
What makes anaerobic glycolysis different to aerobic glycolysis?
Same as aerobic glycolysis EXCEPT Pyruvate molecules are reduced by the NADH - reduced pyruvate = lactate
7.5 Understand the role of the link reaction
Where does the link reaction occur?
The matrix
7.5 Understand the role of the link reaction
What are the products of the link reaction?
- Acetyl CoA
- 2CO2
- 2 NADH + H+
7.5 Understand the role of the link reaction
What occurs in the link reaction?
Pyruvate goes into the link reaction
Pyruvate is oxidized
2x NAD to nADH
Pyruvate is decarboxylates to form Acetate
Acetate and coenzyme A join to form Acetyle coate
Coenzyme A transports acetate to Krebs cycle
Enzyme removes CO2 and hydrogen from pyruvate It is decarboxylates resulting in 2CO2 as a waste product and pyruvate is dehydrogenated releasing two hydrogens that are taken up by NAD to form 2NADH.
7.5 Understand the role of the Krebs cycle
Where does the Krebs Cycle occur?
Matrix
7.5 Understand the role of the Krebs cycle
What products are formed in the Krebs cycle?
- 2 ATP
- 2FADH2-> 4ATP
- 4CO2
- 6NADH + H+
7.5 Understand the role of the Krebs cycle
What occurs during the Krebs Cycle?
- Acetyl CoA enters the Krebs cycle
- 2C acetyl group joins a 4C sugar to form 6C group
- Oxidative decarboxylation of 6C sugar to 5C compound producing CO2
- Oxidative decarboxylation of 5C to 4C producing CO2
- The process is oxidative as NAD+ and FAD are reduced by the addition of hydrogen
- 2CO2 are produced per molecule of pyruvate
- Along with this 3NADH + H+ form FADH2 per molecule of pyruvate
- One ATP is produce at substrate level phosphorylation
- NADH and FADH2 provide electrons to ETC
7.6 ATP is synthesised by oxidative phosphorylation + ETC
What is oxidative phosphorylation specifcally within the Electron Transport Chain?
- Electrons (from reduced NAD/Reduced FAD) pass along the electron transport chain
- Electrons lose energy
- Energy used to phosphorylate ADP to make ATP
- ATP synthase produces ATP; by the movement of H+ ions by chemiosmosis (down the electrochemical gradient) - oxygen is the final acceptor
7.6 ATP is synthesised by oxidative phosphorylation + ETC
Where does the ETC occur?
Inner mitochondrial membrane
7.6 ATP is synthesised by oxidative phosphorylation + ETC
What occurs during the ETC?
Hydrogen is transferred to the ETC by hydrogen which carries NADH + FADH2
Hydrogen ions will release electrons which are transfered between carries which releases energy
This pumps H+ from matric to inner membrane space
H+ accumulates in the inner membrane space and creates a conc. gradient
H+ ions return to matrix travelling through ATP synthase
Down this electron chemical gradient
ATP is produced by chemiosmosis
Oxygen is the final electron acceptor
Oxygen with H+ ions + electrons to make H2O
7.7 Lactate after a period of anaerobic respiration in animals.
What occurs when aerobic respiration occurs after lactic acid build up?
Lactate taken to liver - oxygen debt/EPOC - used to convert lactate back into pyruvate - with production of NAD - pyruvate converted to glycogen
7.9 i) Know how to calculate cardiac output.
What is cardiac output
Volume of blood pumped by the heart in a minute
7.9 i) Know how to calculate cardiac output.
How is adequate oxygen supply maintained when when running?
- Heart rate increases
- stroke volume increases
- SAN activity increases
- AVN time delay decreases
- Increased venous return (more blood returns to the heart)
- ventricles contract with more force
7.9 ii) Variations in ventilation and cardiac output enable rapid delive
How is oxygen supply decreased at lower heart rate?
- Heart rate decreases
- Stroke volume decreases
- SAN activity decreases
- AVN time delay increases
- Decreased venous return
- Ventricles contract with less force
7.9 i) Know how to calculate cardiac output.
Cardiac Output equation
Cardiac Output=Stroke Volume x Heart Rate
7.9 i) Know how to calculate cardiac output.
What is the cardiac output dependent upon/What is the stroke volume?
Volume of blood ehected from the left ventricle (this is the stroke volume)
7.9 i) Know how to calculate cardiac output.
During excercise more blood returns to the heart in what is known as…
Venous return
7.8 i) Know the myogenic nature of cardiac muscle.
What makes the heart myogenic?
Its ability to beat without input from the nervous system.
7.8 i) Know the myogenic nature of cardiac muscle.
What causes contraction of the cardiac muscle?
small electrical charges
7.8 i) Know the myogenic nature of cardiac muscle.
What is polarised and depolarised?
Polarised: slight positive charge on the outside
Depolarised: reversing positive charge
Change in polarity speads from cell to cell and causes cell contraction
7.8 i) Know the myogenic nature of cardiac muscle.
How does depolarisation start? Describe its location and
At the SAN (Sino Atrial Node) Pacemaker
Small area of specialised muscle fibres located in right atrium, beneath opening of superior vena cava
7.8 i) Myogenic nature of heart + roles of the sinoatrial node (SAN)
What is the role of the SAN?
Generates an electrical impulse
Spreads across right and left atria, causing them to contract
Impulse also travels to AVN, impulse in conducted at ventricles after 0.13 seconds
7.8 i) Myogenic nature of heart + the atrioventricular node (AVN)
What is the role of the AVN?
Conducts impulse to the ventricles, after 0.13 second delay
7.8 i) Myogenic nature of heart + the atrioventricular node (AVN)
What is the importance of the delay?
The delay ensures that the atria are finished contracting and the ventricles have filled with blood before they contract.
7.8 ii) Myogenic nature of heart + Bundle of His/Purkyne Fibres
When does the signal reach the Purkyne Fibres?
After the delay at the AVN. These specialised muscle fibres conduct impulses rapidly to the tip of the ventricles.
They continue around each ventricle and divide into smaller branches that penetrate the ventricular muscle. Branches carry the impulse to the inner cells of the ventricle.
7.8 ii) Myogenic nature of heart + Bundle of His/Purkyne Fibres
Collective name of the right and left bundle of fibres?
Bundle of His
7.8 ii) Myogenic nature of heart + Bundle of His/Purkyne Fibres
Which ventricular cells are depolarised cells first and how does this cause contraction?
The ventricular cells that are depolarised first are at the apex of the heart and travel upward to the atria.
This causes contraction upwards from the ventricles pushing blood into aorta and pulmonary artery.
7.8 iii) ECGs can aid the diagnosis of CVD
How does an ECG work?
ECG electrodes attached to the chest and limbs to record electrical current during cardiac cycle.
7.8 iii) ECGs can aid the diagnosis of CVD
What are the four ECG stages?
- P wave
- PR interval
- QRS interval
- T wave
7.8 iii) ECGs can aid the diagnosis of CVD
What does the P wave represent?
Depolarisation of the atria aleading to atrial contraction (atrial systole)
7.8 iii) ECGs can aid the diagnosis of CVD
What does the PR interval represent?
The time taken for impulses to be conducted from the SAN across the atria to the ventricles, through the AVN.
7.8 iii) ECGs can aid the diagnosis of CVD
What does the QRS complex represent?
Wave of the depolarisation resulting in contraction of the ventricles (ventricular systole)
7.8 iii) ECGs can aid the diagnosis of CVD
What does the T wave represent?
Repolarisation of the centricles during the hearts relaxation phase (diastole)
7.8 iii) ECGs can aid the diagnosis of CVD
A heart reate less than 60 bpm is known as…
Bradycardia
7.8 iii) ECGs can aid the diagnosis of CVD
A heart rate over 100 bpm is known as…
Tachycardia
7.8 iii) ECGs can aid the diagnosis of CVD
Irregular heartbeat is known as…
Arrythmia
7.8 iii) ECGs can aid the diagnosis of CVD
What can an ECG do?
- Provide information about abnormal heartbeats, areas of damage or inadequate blood flow
- CVD can cause ischemia - normal electrical activity and rhythm of heart disrupted
7.9 ii) cardiovascular control centre in the medulla oblongata.
What are the three receptors involved in nervous control of the heart?
- Detecting blood CO2 conc./pH - Chemoreceptors - carotid body in aorta and in medulla
- Detecting blood pressure - Baroreceptors - carotid body in aorta
- Detecting muscle contraction - stretch receptors - in muscles
7.9 ii) cardiovascular control centre in the medulla oblongata.
Where is cardiovascular control centre located
Medulla oblongata
7.9 ii) cardiovascular control centre in the medulla oblongata.
What are the two types of nerves going from the cardiovascular control centre to the heart?
Sympathetic nerve (accelerator) and Vagus nerve-Parasympathetic nerve (decelerator)
7.9 ii) cardiovascular control centre in the medulla oblongata.
What causes SAN node to be stimulated?
The sympathetic nerve-this increases the heart rate
7.9 ii) cardiovascular control centre in the medulla oblongata.
What slows down the heart rate?
Vagus nerve
7.9 ii) cardiovascular control centre in the medulla oblongata.
What does the cardiovascular control centre detect?
Accumulation of CO2, reduction of O2, lactate in blood and increased temperature
7.9 ii) cardiovascular control centre in the medulla oblongata.
How does the sympathetic nerve allow muscles to move more quickly?
When a stimuli is notices the impulses of stretch receptors are stimulates
They send impulses to the CCC
Raises the heart rate via the sympathetic nerve
Increase in venous return leading to rise in stroke volume
Elevated heart rate and stroke volume increase cardiac output so more O2 transported and muscles move quicker.
7.9 ii) cardiovascular control centre in the medulla oblongata.
How is blood pressure prevented from rising too far?
Inhibitory nerve impulses are sent from aorta and carotid artery (which detece pressure rising by pressure receptors) to the sinoatrial node.
negative feedback
7.9 ii) cardiovascular control centre in the medulla oblongata.
What are the hormones that effect heart rate and how?
Stimulation of SAN: Noradrenaline - excites SAN - heart rate increases
like vagus nerve stimulation
7.9 ii) nervous control of ventilation
Where is the respiratory control center located?
Respiratory control centre - medulla oblongata
7.9 ii) nervous control of ventilation
How is stimuli detected (CO2) for ventilation?
Detecting blood CO2 conc is done by chemoreceptors - carotid body in aorta and in medulla
Detecting lung inflation - Stretch receptors - in bronchioles
7.9 ii) nervous control of ventilation
How does ventilation cycle usually occur in the body?
Ventilation centre in medulla sends impulse to diaphragm and external intercostal muscles
The external intercostal muscles and diagphram contract simultaneously while the internal intercostal muscles will relax.
7.9 ii) nervous control of ventilation
What is the response to low pH/High CO2
- High carbon dioxide in alveoli
- CO2 diffuses down concentration gradient into bloodstream
- Carbonic acid produced/pH decreases Chemoreceptors in carotid body detect pH fall
- impulses sent to the ventilation centre in medulla
- Impulses sent from medulla to diaphragm and EI muscles to increase rate and strength of muscle contractions
- Breathing rate increases
- CO2 removed from alveoli
7.9 ii) nervous control of ventilation
What is the response to lactate buildup?
- Lactate builds up in blood
- pH fall detected by chemoreceptors
- Impulses sent to ventilation centre
- Impulses from ventilation centre to diaphragm and EI muscles increase
- breathing rate increases
- Oxygen debt/EPOC
- lactate converted into pyruvate
- pH increases to normal
7.11 i) Understanding the meaning of negative and positive feedback
What is homeostasis?
maintenance of a constant internal environment
7.11 i) Understanding the meaning of negative and positive feedback
What are receptors
detect deviations from the norm value fo a certain biological condition
7.11 i) Understanding the meaning of negative and positive feedback
What are effectors and stimuli?
- Effectors: (muscles and glands) that bring condition back to the norm
- Stimuli: (nerve impulses and hormones) activate action by effectors
7.11 i) Understanding the meaning of negative and positive feedback
What is negative feedback?
A deviation from the norm results in effectors bringing about a shift back towards the norm.
7.11 i) Understanding the meaning of negative and positive feedback
What is positive feedback?
A deviation from the norm results in effectors bringing about a further shift away from the norm.
7.12 Understand homeostasis and its importance in maintaining the body
Why is body temperature regulation important?
- Low temperature, enzymes less active and hgih temperature is required for the metabolic rate to rise
- If temperature rises more, enzymes will denature
7.12 Understand homeostasis and its importance in maintaining the body
What is the role of the hypothalymus?
- Contains thermoreceptors
- Detects changes in core body temperature
- Heat loss and Heat gain centre which work to change temperature of the body
7.12 Understand homeostasis and its importance in maintaining the body
What are the effectors that regulate body temperature?
- Sweat glands: Too hot->secrete sweat - sweat evaporates - heat energy taken away from skin
- Skeletal muscle: Too cold->shivering (involuntary muscle contraction) - needs aerobic respiration/ATP - heat energy released
- Erector muscles: Too cold->contract - hairs raised - traps a layer of air to insulate the body
- Liver:->Too hot=raises metabolic rate
*
7.12 Understand homeostasis and its importance in maintaining the body
What is the vascular response to do with blood vessels in thermoregulation?
- Vasoconstriction: constriction (narrowing) of blood vessels
- Vasodilation: dilation (widening) of blood vessels
7.12 Understand homeostasis and its importance in maintaining the body
How are effectors triggered using the hypothalymus?
- Hymopthalymus thermoreceptors detect temperature change
- Heat loss centre sends impulses down motor neurons to effectors (e.g. sweat glands)
- Effectors control temperature (e.g. sweat glands produce sweat)
7.16 Genes can be switched on and off by DNA transcription factors
What is transcription initiation?
Transcription factors and RNA polymerase (transcription-initiation complex) bind to DNA promoter region - only then can transcription process
7.16 Genes can be switched on and off by DNA transcription factors
What are transcription factors?
- A protein that controls the rate of transcription of genetic information from DNA to messenger RNA
- Most inactive transcription factors are activated by the action of hormones/
7.16 Genes can be switched on and off by DNA transcription factors
How are genes turned on?
Transcription factors - bind to promoter region - RNA polymerase can bind - mRNA made - subsequent translation/protein synthesis etc.
7.16 Genes can be switched on and off by DNA transcription factors
How are genes turned off? (Two options)
A protein repressor molecule:
1)They bind to the promoter region preventing attachment of transcription factors
2)They bind to transcription factors preventing attachment to promoter region
RNA polymerase cannot transcribe the gene to make messenger RNA - gene remains switched off
7.16 Hormonal effect on transcription
What is the steroid hormone and how does it affect transcription?
e.g. testosterone
Steroid hormone passes through cell membrane - hormone binds to receptor - hormone-receptor complex functions as a transcription factor
7.15 Discuss ethical positions on using performance enhancing drugs
Reasons that you SHOULD use performance enhancing drugs?
Impossible for all drugs to be detected and too difficult to regulate PEDs - no ban on dietary supplements; where do we draw the line? - sports isn’t fair play anyway
7.15 Discuss ethical positions on using performance enhancing drugs
Reasons that you SHOULD’NT use performance enhancing drugs?
Gives some an unfair competitive advantage - can result in health problems and early death (e.g. EPO cyclists)
