Animal Responses Flashcards
What two are the two systems that the nervous systems split into
CNS- made of brain and spinal cord
Peripheral nervous system- Made up of what connected CNS to rest of body
What are two systems of peripheral nervous system
Somatic NS: Controls conscious activities e.g. running and planning video games
Autonomic NS: Controls unconscious activities e.g. digestion
What are two divisions of the autonomic nervous system
Sympathetic nervous system: gets the body ready for action- fight or flight
Parasympathetic NS- calms the body down
What do sympathetic nerves do
Raise heart rate by secreting noradrenaline
What do parasympathetic nerves do
Slows heart rate by secreting acetylcholine
Difference between anterior pituitary and posterior pituitary gland
Posterior pituitary only stores and releases hormones sent from the hypothalamus such as ADH and oxytocin. Anterior pituitary produces and releases hormones
Where is cerebrum found in brain and whats its function
Largest part of brain
Divided into two parts- cerebral hemispheres
Cerebral cortex is a thin outer layer which is folded
Cerebrum is involved in hearing, vision, learning and thinking
Where is hypothalamus and whats its function
Found beneath the middle part of the brain. It monitors temperature of blood flowing through it.
Produces hormones that control pituitary gland
Where is the medulla oblong at a in brain and its function
It’s at the base of the brain, at the top of the spinal cord
Automatically controls breathing and heart rate
Where is cerebellum and its function
Underneath the cerebrum and has a folded cortex
Important for muscle coordination, posture and coordination of balance
What is a reflex
Responses to the environment that are not processed by the brain
What are two effectors in the blinking reflex
Orbicularis oculi muscle- pulls eyes inward
Superior levator palpebrae- lowers the eyelid
How does the NS help control heart rate
SAN generates electrical impulses that cause the cardiac muscles to contract
Rate at which SAN fires (HR) is unconsciously controlled by medulla
Need to alter HR to respond to internal stimuli e.g. prevent fainting due to low blood pressure
Stimuli detected by pressure receptors and chemical receptors
How does the medulla respond to high/low pressure
High blood pressure: detected by baroreceptor. Impulses sent to the medulla which sends impulses across vagus nerve. This secretes acetylcholine, binding to receptors on SAN
Low blood pressure- detected by baroreceptor.
Impulses sent to the medulla which sends impulses along the accelerator nerve. Secretes noradrenaline, binds to receptors on the SAN
How does medulla respond to high o flow PH levels
High PH: Detected by chemoreceptors- impulses sent to the medulla which sends impulses along the vagus nerve. Secretes acetylcholine, binds to receptors on the SAN
Low PH: Detected by chemoreceptors. Impulses are sent to the medulla which sends impulses along the accelerator nerve. Secretes noradrenaline, binds to receptors on SAN
What is T test for
Whether a significant difference between means of 2 data sets
What’s the impact of adrenaline
Increases
Decreases blood flow to gut by vasoconstriction
Increase blood flow to heart and muscles by vasodilation
What are skeletal muscles made from
Muscle fibres- Cell membrane of this is called sarcolemma
Bits of sarcolemma fold inwards across muscle fibres and stick into the sacroplasm- which are called Transverse Tubules and help spread electrical impulses throughout the sarcoplasm so they reach all parts of muscle fibre
What is the sarcoplasmic reticulum
Network of internal membranes, stores and releases calcium ions needed for muscle contraction
What organelle do muscle fibres have which is important
Have a lot of mitochondria to provide ATP thats needed for muscle contraction
What are myofibrils
Long, cylindrical organelles which are made of proteins and highly specialised for contraction
What are microfibrils made up of
Contain bundles of thick and thin myofilaments that move past each other to make muscles contract
Thick myofilaments are made of the protein myosin
Thin myofilaments are made up of the protein actin
What does a microfibril look like under a microscope
Dark bands contain thick myosin filaments and overlapping thin actin filaments- A bands
Light bands contain thin actin filaments only- L bands
What are sacromeres
Short units which make up microfibrils
What is the Z line
Line which marks the end of a sarcomere
What can be found in the middle of each sarcomere
M line- middle of myosin filaments
Around the M line is the H zone
H zone only contains myosin filaments
What’s the sliding filament theory
Myosin and actin filaments slide over each other to make sarcomere a contract
Simultaneous contraction of lots of sacromeres means that the myofibrils and muscle fibres contract
Sacromeres return to original length as muscle relaxes
What happens to the different bands in sarcomere as it contracts
A band stays same
L band gets shorter
H zone gets shorter
What are some features of myosin filaments
Myosin filaments have globular heads that are hinged, so can move back and forth
Each myosin head has a binding site for actin and binding site for ATP
Actin myosin binding sites
Tropomyosin and troponin are found between actin filaments
What happens to binding sites of resting muscles
Actin- myosin binding site is blocked by tropomyosin, which is held in place by troponin
So myofilaments can’t slide past each other because the myosin heads can’t bind to actin-myosin binding site in actin filaments
How does an action potential trigger muscle contraction
Action potential from a motor neurone stimulates a muscle cell, depolarising the sarcolemma, which depolarising spreads down T tubules to sarcoplasmic reticulum
Causes sarcoplasmic reticulum to release stores Ca2+ ions into sarcoplasm
These bind to troponin causing it to change shape, pulls attached tropomyosin out of the binding site on the actin
Exposes the binding site allowing the myosin head t bin- this bind formed when a myosin head binds to actin filament- actin-myosin cross bridge.
Ca2+ ions also activate the enzyme ATPase which breaks down ATP to provide energy- this moves the myosin head which pulls the actin
Myosin head detached once moved and reattached
What happens when the muscle stops being stimulated
Calcium ions leave binding sites on the troponin and are moved by active transport back to sarcoplasmic reticulum
Troponin molecules return to their original shape, pilling attached tropomyosin molecules with them
Means the tropomyosin molecules block the actin myosin binding sites again
Actin filaments slides back to relaxed position which lengthens the sarcomere
What is a neuromuscular junction
Synapse between motor neurone and muscle cell
Use transmitter acetylcholine to bind to nicotine cells cholinergic receptors
Same way as synapses which release neurotransmitter and trigger depolarisation in postsynaptic cell
Causes it to contract
What happens when a chemical blocks the release of a neurotransmitter or blocks the receptor site
May prevent the action potential from being passed onto the muscle so the muscle won’t contract
Could be fatal if effects the muscles involved in breathing
If can’t contract ventilation can’t occur and can’t dealire anaerobic
What is the structure and function of skeletal muscle
Control is conscious
Made from muscle fibres with many nuclei
Cross satiations on a microscope
Some contract quickly and used for speed and strength but fatigue quickly, and some slow which fatigue slow and used for endurance and posture
What’s the structure and function of involuntary muscle
Also called smooth muscle
Controlled unconsciously
Found in walls of hollow internal organs, e.g. in gut contracts t move food along
One nucleus
Slowly and don’t fatigue
How could you monitor muscle fatigue
Monitor electrical signals and musk as contract in response to these
Can be detected by electrodes placed on the skin
Connected to a computer to allow electrical signals to be monitored
Is called electromyography
What are baroreceptor
Pressure receptors in the aorta and vena cava
Detect high or low blood pressure and send nerve impulses along sensory neurons to cardioregulatory centres in the medulla oblongata
What is the vagus and accelerator nerve
In the medulla oblongata
Accelerator carries impulses from cardioacceleratory centre.
Vagus nerve carries impulses from the cardioinhibitory centre
What are prociporeceptors
Stretch receptors which detect movement by cardiovascular muscle highlighting a need for oxygen
What are chemoreceptors
Receptor that responds to a change in chemical composition of fluid around it
Found in arteries aorta and blood
What does noradrenaline do
Binds to receptors on the SAN to increase heart rate
What does cortisol do and where’s it secreted from
Stimulates target organs and tissues to increase blood pressure, blood glucose and suppress immune system.
Released by the cortex of the adrenal gland
How does aerobic respiration produce ATP
Myoglobin will only release 02 in very low po2
ATP generated via oxidative phosphorylation in mitochondria
How does anaerobic respiration produce ATP
Produces ATP by rapid glycolysis. Produces pyruvate which is converted to lactate by lactate fermentation
How does the ATP creatine phosphate system work
Creatine phosphate provides a phosphate which binds to ADP to produce ATP
Can only occur for a few seconds- anaerobic and doesn’t produce Laura’s
3 ways to generate ATP
- Aerobic respiration
- Anaerobic respiration
- ATP-CP system
How does action potentials trigger contraction of muscles
- Trigger depolarisation of sarcolemma
- Electrical impulse travel down transverse tubules towards sarcoplasmic reticulum
- Sarcoplasmic reticulum triggers release of calcium ions
- Calcium ions bind to troponin causing it to change shape. Pulls tropomyosin out of actin-myosin binding site
How do calcium ions initiate contraction in skeletal muscle fibres
Activates ATPase which breaks down ATP into ADP and P to release energy that moves myosin head
What is a sarcomere
Unit of a muscle fibre
What is the sarcomella
Muscle cell membrane
What are the structures of a microfibril
L band- thin actin
H zone- only myosin
Z- protein discs that hold microfilamentd in place
A band- overlap of actin/myosin darker
How does actin-myosin binding happen
Tryomyosin held in place by troponin molecules where calcium ions released by the sarcoplasmic reticulum, binds to troponin molecules
Causes troponin to change shape and release tropomyosin to expose the binding site.
Myosin head contains ATP > ADP+ P
Allows to move into extended position ready to spring into action. Binds to actin and changes shape, pulling actin and shortening’s the sacromere. Actin and myosin still bonded- unbinds with ADP so can bind to fresh atp
Changes shape and release actin
Difference between NMJ and synapse
Only releases acetylcholine
Between motor neurone and skeletal
NMJ always excitatory
What causes muscle fatigue
Calcium channels become leaky, so muscle can’t can’t fully contract or relax
Lack of atp
Lack of 02
Lactase build uo
What causes muscle cramps
Build up of lactic acid
ATP depletion
Ion imbalance
What is an antagonistic pair
Muscles working together, such as biceps and triceps to move bones.
One muscle in pair contracts, and other relaxes
Arm, biceps contracting lifts the lower arm, and triceps contracting lowers it
What is a synergist
Muscle which aids a prime mover in a movement and helps prevent rotation (surrounds joints)
Three types of muscle
Skeletal, cardiac, smooth
Features of cardiac muscle
Myotonic
Intercalated discs which connect fibres
Packed with mitochondria
Contract rhymetically and don’t fatigue
What are features
What are features of skeletal muscle
Voluntary, consciously controlled
Fast twitch muscle fibres and slow twitch muscle fibres
Cross striations and many nuclei
What are features of smooth muscle
Lack cross striations
Found in walls of hollow organs
Spindle shaped
Contract slowly and dont fatigue
How do antagonistic pairs work in the elbow
Tendons connect muscle to the bone (bicep muscle connected to radius and ulna)
Ligaments hold bones together to prevent dislocation
The synovial membrane secretes synovial fluid to prevent friction
