Animal Responses Flashcards
what connects both hemispheres of the brain
the corpus callosum
what three things protects the CNS
1) meninges fluid
2) cerebrospinal fluid
3) skull and vertebrate bones
name the four lobes of the brain
frontal lobe
parietal lobe
occipital lobe
temporal lobe
describe the cerebrum
largest part of the brain
2 hemispheres
connected by corpus callosum
surface area of approx 2.5m2
what is the cerebral cortex
a thin layer of nerve cell bodies known as the cerebral cortex
what is the function of the cerebral cortex
- conscious thought and emotional responses
- ability to override some reflexes
- intelligence, reasoning, judgement, imagination
what are the three areas of the cerebral cortex
sensory areas- recieve impulses from receptors
association area- interpret the input and judge the appropriate response
motor areas- send impulses to effectors ( muscles and glands)
what are the functions of the cerebellum
fine tunes muscles for body position, to remain upright and balanced
fine tunes tensioning and feedback
operation of antagonistic muscles
what is the function of the hypothalamus
managing hormone levels
controlling codys homeostatic mechanisms, eg temp control and osmoregulation
controls autonomic nervous system
describe osmoregulation
blood flows through the hypothalamus and the water potential is monitored
hypothalamus produces ADH which is stroed in the pituitary gland
released in blood when water potential of blood drops
what does the pituitary gland regulate
hunger, thirst, body temp, reproductive hormones, ADH and ACTH
what does the medulla oblongata regulate
breathing rate
heart rate
circulation
swallowing, salivation, vomiting reflex
what does the medulla oblongata control
all involuntary muscles
what are the two parts of the pituitary gland
anterior (front)
posterior (back)
what are the two divisons of the CNS
brain and spinal cord and (intermediate neurons)
what is the peripheral nervous system
sensory and motor neurones that transmit impulses to and from the CNS
what can the peripheral nervous system be divided into, what can this further be divided into
peripheral:
1) somatic
2) autonomic
autonomic:
1) sympathetic
2) parasympathetic
what does the somatic nervous system
controls voluntary movements
motor neurones, myelinated neurones
what does the autonomic nervous system do
controls involuntary movement
what are the two divisions of the autonomic nervous system and what are there functions
sympathetic- fight or flight, motor unmyelinated neurones to smooth muscles or glands
parasympathetic- rest or digest, motor unmyelinated neurones to smooth muscles or glands
what neurotransmitter is involved in either the sympathetic or parasympathetic branch
sympathetic- noradrenaline
parasympathetic- acetylcholine
what are 2 of the differences between the autonomic and somatic nervous system
autonomic= unmyelinated motor neurones somatic= myelinated motor neurones
autonomic= 2 motor neurones to effector somatic= 1 motor neurone to effector
what is the ganglion
a specialised synapse of peripheral nervous system outside of the brain
what are some of the differences between sympathetic and parasympathetic nervous system
symp= most active in times of stress parasym= most active in times of relaxation
symp= ganglion outside of spinal cord parasymp= ganglion within the target tissue
symp= post ganglionic neurones secrete noradrenaline parasymp= post ganglionic neurone secrete acetylcholine
what are the three types of muscle
skeletal muscle
cardiac muscle
involuntary muscle
describe skeletal muscle
striated cylindrical cells are multinucleate found attached to bone controlled by somatic nervous system contracts quickly, tires easily
describe involuntary muscle
unstriated
spindle-shaped cells each have a single nucleus
found in the walls of tubular structures, such as the gut, blood vessels and ducts
controlled by autonomic nervous system
contracts slowly, fatigues slowly
describe cardiac muscle
semi-striated cylindrical cells each with a single nucleus found only in heart controlled by the ANS contracts spontaneously without fatigue
what is the function of cardiac muscle
to pump blood around the body
myogenic
what is the purpose of intercalated discs in cardiac muscle
membrane with gaps for free ion diffusion, for quick and easy action potential transmission
where do we find involuntary muscle
intestine walls
iris of the eye
blood vessel walls
bronchi/ bronchioles
what is the muscle fibre that makes up skeletal muscle composed of
many myofibrils
each myofibril is made up of thin actin protein and thick myosin
what happens when a action potential reached a neuromuscular junction
1) action potential causes Ca2+ ion channels to open and this causes vesicles to fuse with pre-synaptic membrane, releasing acetylcholine by exocytosis
2) Ach binds to receptors assosciated with Na+ ion channels in muscle fibre membrane (sarcolemma)
3) na ion channels open in sarcolemma and na+ move into muscle fibre- depolarisation of t tubule system
4) t tubule system depolarisation causes ca2+ ions stored in the sarcoplasmic reticulum to be released
5) calcium ions bind to muscle protein troponin which causes muscle contraction
6) acetylcholinesterase breaks down acetylcholine to reverse the process
what are motor units
when different degrees of muscle contraction are required. branched neurones at the muscular junctions attach to a cluster of muscle cells
the more motor units stimulated the greater the force of contraction
Which section of a sarcomere contains:
1) only myosin
2) only actin
3) both actin and myosin
1) H zone
2) I band
3) A band
What does the mnemonic AIMHAMA mean
Actin I band
Myosin H band
Actin myosin A band
What is the sarcomere
The distance between two Z lines
Describe the thickness of myosin and actin
Actin is thin
Myosin is thick
What is troponin
What happens when it changes shape
A protein complex that changes shape when Ca2+ ions bind to it causing tropomyosin to move which exposes the actin myosin binding site
Describe the process of sliding filament hypothesis
1) ATP detaches myosin head from actin myosin bunting site on actin
2) hydrolysis of ATP to ADP + Pi to give energy to resit the myosin head
3) sarcoplasmic reticulum releases Ca2+ as action potential reaches neuromuscular junction
4) Ca2+ binds to troponin
5) troponin changes shape, tropomyosin moves exposing the actin- myosin bonding site
6) myosin head attaches to actin myosin binding site forming cross bridges
7) the ADP and Pi molecule is released and the myosin head moved, causing actin filaments to slide past the stationary myosin filaments
What is ATP used for in the sliding filament hypothesis
ATP is needed to provide energy to cock the myosin head so it can bind to actin
ATP is needed to break the cross bridges
ATP is needed to actively transport Ca2+ from sarcoplasm back into the reticulum
Why do fast twitch muscles store creatine phosphate
Can donate a phosphate to restore ATP as follows. This needs phosphocreatinase enzyme
What are the cardiovascular centres connected to
The SAN
What nervous system controls the SAN
The accelerator nerve which increases heart rate is controlled by sympathetic nerve
The vagus nerve which decreases heart rate is controlled by parasympathetic nervous system
What do the vagus and accelerator nerve control
The frequency of contraction
What neurotransmitter is secreted by accelerator nerve
Describe the pre-ganglionic neurone
Noradrenaline
Short
What neurotransmitter is released at vagus nerve
Describe pre-ganglionic neurone
Acetylcholine
Long preganglionic neurone
What happens when exercising
-CO2 levels increase which lowers pH of blood due to HCO3- ions
-chemo receptors detect change and send message to cardiovascular centre in medulla oblongata
-accelerator centre increases frequency of action potentials down synpathetic nerve to SAN
-SAN nose increases wave of excitation
↪️increases blood flow CO2 is removed quicker
What happens when blood pressure increases
-Stretch receptors (baroreceptors) detect change and send impulses to CVC in medulla oblongata
-inhibitory centre increases frequency of impulses down vagus nerve to SAN
-SAN nose decreases wave of excitation
↪️heart rate decreases and blood pressure returns to normal
Name 5 physiological changes that happen in the fight or flight response
1) pupils dilate
2) blood flow to gut decreases
3) heart rate increases
4) ventilation rate increases
5) metabolic rate increases
Why do bronchioles dilate in flight or fight
Involuntary muscle relaxes
More O2 enters lungs and diffuse into blood
Name two other mechanisms animals have to fight or flight
Play dead
Camouflage
Describe the massive long process of how the hormonal and SNS work together in the fight or flight response
1)receptor receives auditory /visual threat
2) nerve impulse transmitted along sensory neurone To cerebral cortex and hypothalamus is activated:
1️⃣nervous system
1) activated SNS
2) adrenal medulla releases adrenaline and noradrenaline into blood
2️⃣endocrine system
1) releases CRF into pituitary gland
2) anterior pituitary gland releases hormone ACTH
3) ACTH causes adrenal cortex to release hormones like cortisol into blood
↪️fight or flight response
⭐️Describe second messenger model⭐️
Adrenaline is 1st messenger: binds to receptors
Activates enzyme adenyl Cyclase which can convert many ATPs into many cAMP
cAMP second messenger activated many other enzymes in different cells
In this case Glycogen Phosphorylase (causes glycogenolysis)
What happens to the bands when the myofibril contracts
A band remains constant
I band decreases
H zone decreases
Z lines move closer together
Explain how an increased concentration of hydrogen ions leads to a reduction in the force of contraction of the muscle (reduces ability for calcium ions to bind)
Fewer calcium ions bind to troponin
Fewer troponin changes shape
Fewer tropomyosin moves
Fewer binding sites on actin available
Fewer actin myosin cross bridges
Power stroke reduced
Actin filaments pulled past myosin with less force
