Animal responses Flashcards
what is the CNS made up of ?
brain and spinal cord
what is the peripheral nervous system made up of ?
rest of neurones that connect CNS to rest of body
what does somatic nervous system control ?
conscious activities
what are the two functional systems of PNS ?
somatic and autonomic
what are the two divisions of the autonomic nervous system ?
sympathetic and parasympathetic
what is the role of the sympathetic nervous system ?
gets body ready for ‘fight or flight’
what is the role of the parasympathetic nervous system ?
puts body into a constant normal state (rest and digest)
what neurotransmitter released from sympathetic nervous system neurones ?
noradrenaline
what neurotransmitter released from parasympathetic nervous system neurones ?
acetylcholine
state the function of pituitary gland
releases hormones and stimulates other glands (e.g. adrenal)
state function of medulla oblongata
controls breathing and heart rate
state the function of cerebellum
coordinates muscles, balance and posture
state the function of cerebrum
involved in hearing, seeing, learning and thinking
outline the process of blinking reflex
- sensory neurones (in cornea) stimulated by touch
- impulse sent sensory -> relay -> motor
- motor carries impulse to effector (orbicularis oculi muscles)
- muscle contracts, closing eye
what is beneficial of knee jerk reflex ?
maintains balance and posture
outline the process of knee jerk reflex
- stretch receptors in quadriceps detect muscle stretch
- impulse passed sensory -> motor in spinal cord
- motor carries to effector (quadriceps muscles)
- muscle contracts, leg moves forward
how is fight or flight response initiated ?
- nerve impulses from sensory neurones arrive at hypothalamus
- hormonal and sympathetic nervous system activated
how is hormonal system involved in the initiation of fight or flight response ?
- pituitary gland releases hormone ACTH
- ACTH causes cortex of adrenal gland to release steroidal hormones
how is sympathetic nervous system involved in the initiation of fight or flight response ?
triggers release of adrenaline from medulla of adrenal gland
state and explain 5 effects of adrenaline
- heart rate increased (more blood pumped)
- smooth muscle in airways relaxes (more oxygen)
- glycogenolysis (more energy)
- blood diverted to muscles/heart/lungs (smooth muscle contracting/relaxing)
- erector pili muscles contract so hairs stand (animal looks bigger)
involving the heart, where are baroreceptors based and what is their function
- based in aorta and vena cava
- detect high / low pressure
involving the heart, where are chemoreceptors based and what is their function
- aorta / carotid artery / medulla
- monitors oxygen / carbon dioxide / pH levels in blood
how does adrenaline affect the heart ?
- binds to receptors in heart
- causes cardiac muscle to contract more freq. w/ more force
Describe how high blood pressure is brought back to normal
- baroreceptors detect high blood pressure
- impulses sent -> medulla -> vagus nerve
- acetylcholine secreted, which binds to receptors on SAN
- heart rate slows
Describe how low blood pressure is brought back to normal
- baroreceptors detect low blood pressure
- impulses sent -> medulla -> accelerator nerve
- noradrenaline secreted, which binds to receptors on SAN
- heart rate increases
Describe how high p(O2) / pH or low p(CO2) is brought back to normal
- chemoreceptors detect chemical changes
- impulse sent -> medulla -> vagus nerve
- ACh secreted, which binds to SAN
- heart rate decreases
Describe how low p(O2) / pH or high p(CO2) is brought back to normal
- chemoreceptors detect chemical changes
- impulse sent -> medulla -> accelerator nerve
- noradrenaline secreted, which binds to SAN
- heart rate increases
describe / name structures of a muscle fibre
- sarcolemma is the cell membrane
- transverse tubules are folded parts of sarcolemma
- sarcoplasm is cytoplasm
- internal network of membranes called sarcoplasmic reticulum runs through sarcoplasm
- lots of ATP and nuclei
what is function of T tubules ?
spreads electrical impulses throughout sarcoplasm
what is the function of sarcoplasmic reticulum ?
stores and releases calcium ions (voltage gated)
what are thick myofibrils made from ?
protein myosin
what are thin myofibrils made from ?
protein actin
what is A-band ?
dark band containing thick myosin filaments w/ some overlapping thin actin filaments
what is I band ?
light band containing only thin actin filaments
what is a sarcomere ?
short unit of a myofibril containing A band and 2 I bands
what is H zone ?
area around M line, contains only thick filaments
describe the change in lengths of a contracted sarcomere
- sarcomere shortens
- A bands stay same
- I bands shorten
- H zones shorten
what occurs w/ the filaments to cause sarcomere to contract ?
the filaments slide over one another
describe binding sites of sarcomere at rest…
actin-myosin binding site in actin filament blocked by tropomyosin, which is held in place by troponin
outline the process of muscle contraction (6)
- depolarisation of sarcoplasmic reticulum releases Ca ions
- Ca ions bind to troponin, causing shape change
- tropomyosin pulled out of binding site
- myosin head binds, forming actin-myosin cross bridge
- Ca ion activated ATPase breaks down ATP, releasing energy, which moves myosin head, pulling actin filament along
- myosin reattaches to diff binding site …
state the three uses of energy from ATP in muscle contraction
- moves myosin head
- breaks actin-myosin cross bridge
- pumping calcium ions back into sarcoplasmic reticulum
describe how muscle stops contracting
Ca ions leave binding site and are pumped back to sarcoplasmic reticulum — troponin return to shape — tropomyosin pulled back to block binding site
— no myosin heads attached to actin filaments — actin filaments slide back to relaxed position — sarcomeres lengthen
what other process (other than an/aerobic respiration) generates ATP ?
ATP - Creatine Phosphate (CP) system
state the equation for CP system
ADP + CP –> ATP + C
what is CP system ? what is it used for ?
- phosphorylating ADP w/ phosphate group from CP
- very fast process but CP runs out fast so used for short bursts of vigorous exercise
- anaerobic and alactic (no lactate formed)
what is a neuromuscular junction ?
synapse between motor neurone and muscle cell
what neurotransmitter is used at neuromuscular junction and what does it bind to ?
ACh binds to nicotinic cholinergic receptors
describe structure of skeletal muscle
- made up from many muscle fibres w/ lots of nuclei
- regular cross-striations visible under microscope
where is smooth muscle found ?
lining of gut, airways, blood vessels
describe the contraction of skeletal muscle
- some contract quickly (speed and strength) but fatigue fast
- some contract slowly and fatigue slow (endurance and posture)
- in one direction
describe the structure of smooth muscle
- one nucleus for each muscle fibre
- spindle shaped w/ pointed ends
describe the contraction of smooth muscle
contract slowly so don’t fatigue
describe the structure of cardiac muscle
- muscle fibres connected by intercalated discs
- muscle fibres branched to spread impulses
- muscle fibres are cylinder shaped and have one nucleus
- many mitochondrion so don’t fatigue
describe the contraction of cardiac muscle
- myogenic so contracts without nervous system
- contracts rhythmically and relatively fast
what measures muscle fatigue ?
electromyogram
