5.5 Animal Responses Flashcards
Central nervous system
Brain and spinal chord
Peripheral nervous system
Everything except brain and spinal chord
2 systems pns is split into
Sensory (what you sense)
Motor (response to change)
Systems in the motor system
Somatic nervous system (conscious, voluntary responses) and autonomic nervous system (subconscious responses
Two matters in brain
White matter (myelinated neurones)
Grey matter (non myelinated neurones)
Divisions in autonomic nervous system
- sympathetic nervous system = fight or flight
- Parasympathetic nervous system = rest and digest
Sympathetic nervous system’s ganglionic neurones
Pre ganglionic neurones are short and post ganglionic neurones are long
Parasympathetic nervous system’s ganglionic neurones
Pre ganglionic neurones are long and post ganglionic neurones are short
sympathetic nervous system neurotransmitter
Norepinephrine
Parasympathetic nervous system’s neurotransmitter
Acetylcholine
Sympathetic nervous system’s effect on activity
Increases activity
Parasympathetic nervous system’s effect on activity
Decreases activity (conserves energy)
How does the sympathetic nervous system increase ventilation rate
Smooth muscle in lungs relax so bronchioles widen so more air can pass through
Effects of sympathetic nervous system
increases heart rate
• dilates pupils
• increases ventilation rate
• reduces digestive activity
Effects of parasympathetic nervous system
• decreases heart rate
• constricts pupils
• reduces ventilation rate
• increases digestive activity
Compare parasympathetic and sympathetic nervous systems
Sympathetic branches of the nervous system come from the middle of the spinal column come from
The thoracolumbar region
Where do Parasympathetic branches of the nervous system come from mostly higher up the spinal column come from
The craniosacral region
What are the ganglia in the sympathetic nerves close to
Spinal chord
What are the ganglia in the parasympathetic nerves close to
The target organs
Labelled brain diagram
Cerebrum overview
largest part of brain = thinking, memory, thought process
Cerebellum overview
fine tunes movement + helps with balance
Hypothalamus and pituitary gland overview
Homeostatic response
Medulla oblongata overview
autonomic nervous system = controls heart rate, breathing rate
Two parts of pituitary gland
Anterior and posterior
Link between hypothalamus and pituitary gland
Hypothalamus triggers pituitary gland to secrete a specific hormone by producing releasing factors which tells pituitary gland to release hormones
Anterior pituitary gland
produces its own hormones which are released when releasing factors are produced by the hypothalamus
Posterior pituitary gland
hormones are made by hypothalamus but stored in posterior pituitary gland and released when needed.
What hormones can the posterior and anterior pituitary gland produce?
Posterior: ADH and oxytocin
Anterior: any other hormone
Cerebrum areas
Sensory, motor, association
Association area
Compares any sensory input w anything that’s happened in the past
Link in sensory regions of cerebrum
Size of the sensory regions are proportional to the sensitivity of the area e.g. lips would occupy big region in sensory cortex bc v sensitive
Link in motor area of cerebrum
size of regions are to do w how complex the movement is. More complex = bigger
Where are the motor and sensory area of the cerebrum located
Motor area infront of sensory
Relationship in sensory area of brain
- relationship between sensitivity + size of area in brain
Relationship in motor area of brain
relationship between complexity of movement and size of brain
Where is the medulla oblongata located
At the back of the neck
Centres in the medulla oblongata
Cardiac centre, respiratory centre, vasomotor centre
Cardiac centre
Controls heart rate
Respiratory centre
Rate and depth of breathing
Vasomotor centre
Circulation and blood pressure
Reflex
subconscious response w aim of survival
Reflex arc
starts w receptors (detects stimulus) then info fed to sensory neurone which feeds it to the relay neurone (optional) then to motor neurone
Do reflexes go through the brain.
Most never do and only go through the spinal chord
Relay neurone
connects motor and sensory neurone (bridging neurone)
Knee jerk reflex
- right below your patella (kneecap) there’s a tendon which causes your thigh muscles to contract when hit.
- Response should be to kick = extensor muscles contract and flexor muscle relaxes (antagonistic muscles = when one contracts the other relaxes)
- spinal reflex
What does it mean if the knee reflex doesn’t work
There may be a brain issue
What is the knee reflex for
to help you balance and land on two feet. (Survival purpose)
Blinking reflex (corneal reflex)
- Blink if cornea are stimulated e.g. by being touched, loud sounds
- Cranial reflex (goes through the brain) so it can be inhibited
Bling reflex (optical reflex)
- when there’s a reaction to over bright light
- Cranial reflex so it can be inhibited
- In an unconscious person if the blinking reflex is not present, they are in a coma.
Another name for blinking reflex and bling reflex
Corneal and optical reflex
Describe reflexes in 3 words
Involuntary, innate, fast
Physiological changes associated with fight or flight response
Pupils dilate
- heart rate + blood pressure increases
- arterioles in digestive system + skin constrict + muscles and liver arterioles dilate
- blood glucose levels increase
- metabolic rate increases
- erector pili muscles in the skin contract
- ventilation rate + depth increase
- endorphins are released in the brain
Survival value of pupils dilating
Allows more light to enter the eyes, making the retina more sensitive
Survival value of heart rate + blood pressure increasing
Increases the rate of blood flow to deliver more oxygen and glucose to the muscles and to remove carbon dioxide and other toxins
Survival value of arterioles constricting (digestive system + skin) and dilating (muscles + liver)
Diverts blood flow away from the skin and digestive system + towards the muscles
Survival value of blood glucose levels increasing
Supplies energy for muscular contraction
Survival value of metabolic rate increasing
Converts glucose to useable forms of energy e.g. atp
Survival value of erector pili muscles in the skin contracting
Makes hairs stand up = sign of aggression
Survival value of ventilation rate + depth increasing
Increases gaseous exchange = more oxygen enters blood + supplies aerobic respiration
Survival value of endorphins being released in the brain
Wounds inflicted on the mammal don’t prevent activity
2 things that can happen when the hypothalamus activates the sympathetic nervous system
- Impulses activate glands and smooth muscles
- Activates adrenal medulla —> secretion of adrenaline in bloodstream
Both end with neural activity combing in with hormones in the blood stream to cause a fight or flight response
Explain cerebrum to hypothalamus
- inputs feed into sensory centres in cerebrum
- cerebrum passes signals to the association centres
- if threats recognised, cerebrum stimulates the hypothalamus
- hypothalamus increases activity in the sympathetic nervous system + stimulates the release of hormones from the anterior pituitary gland
Process hypothalamus to thyroxine
Hypothalamus releases TRH whcih stimulates pituitary gland to release TSH which tells thyroid gland to secrete thyroxine (role of thyroid: increase metabolic rate)
Process of hypothalamus to corticoid hormones
ACTH binds to adrenal cortex which causes the secretion of the corticoid hormones e.g. cortisol
What controls the SAN in the heart and how
The medulla oblongata = tells it to increase or decrease heart rate + can control how strongly muscles contract in ventricles to increase stroke volume
Does the heart need to be told to beat
No, it’s myogenic = can initiate its own beat but rate of beating is what the brain’s trying to control
Why can’t the brain just leave the heart beat to be myogenic
- Normally = atrial have higher myogenic rate than ventricles = will contract more often than the ventricles = BAD = good system would have these the same = normally can do 60-80 without the brain = good range but beat WOULDNT be synchronised
What does the sympathetic nervous system do to the heart rate and how
Uses the accelerant nerve from the medulla oblongata cardiovascular centre = inputs to SAN and releases noradrenaline = causes heart rate to increase
What does the parasympathetic nervous system do to the heart rate and how
sends action potentials down vagus nerve from the medulla oblongata cardiovascular centre = releases acetyl choline = causes heart rate to decrease
Heart rate increase or decrease process
- brain detects situation change through sensory systems e.g. stretch receptors and chemoreceptors and stretch receptors in the walls of carotid sinus
Stretch receptors
found in muscles of limbs = if limbs are moving more —> receptors detect movement —> sends signal to cardiovascular centre to increase heart rate because more oxygen needed
Chemoreceptors
Found in carotid arteries (arteries from heart to brain = supply brain w oxygen, found on neck)
Brain = monitor pH of blood = high levels of co2 make blood more acidic (carbonic acid) = brain knows heart rate needs to be increased to remove carbon dioxide = uses accelerant nerve to increase heart rate
stretch receptors in the walls of carotid sinus
(area in aorta which plugs into carotid artery) = aim is to monitor blood pressure
Diagram ab how brain controls heart rate
Why can adrenaline increase heart rate on its own
Because it has receptors on the heart
If control of heart rate fails …
use pacemaker which replaces SAN + controls heart by itself
What are 3 types of muscle
Skeletal, cardiac, involuntary/smooth muscle
Diagram of 3 types of muscle
Skeletal muscle
- striated (bc muscle stripey)
- Voluntary muscles e.g. tricep, bicep
- Regularly arranged so muscle contracts in one direction
- Multinucleated
- Contraction speed is rapid but can get exhausted fast aswell
Cardiac muscle
- Striated
- Found in heart
- Involuntary
- Branched
- Uninucleated
- Contracts slower than skeletal but faster than smooth muscle but doesn’t get tired easily
Involuntary/ smooth muscle
- non striated
- Spindle shape = irregular shape/ arrangement
- Uninucleated
- Contract slowly but don’t get tired
Sarcolemma
Plasma membrane of muscle fibre
Sarcoplasm
Muscle fibre’s cytoplasm
T tubules
- dips in sarcolemma
How do neurones tell ur muscle to contract
releases neurotransmitters which go down the t tubules = responds to neural transmission
Mitochondria in muscle cells?
Lots of mitochondria
Sarcoplasmic reticulum
Endoplasmic reticulum of muscle fibres
Filled w calcium ions
Myofibrils
Each branch in muscle fibre (contractile units)
What are myofibrils made up of
Actin (thin protein) and myosin (thick protein w lots of heads)
Fill in the diagram
i band
Just actin
Dark band
Whole length of myosin
Sarcomere
Distance between 2 z lines (functional unit)
Muscle contraction step 1
- Actin filaments have binding sites for myosin heads but tropomyosin blocks the binding site and it’s held in place by the protein troponin
Muscle contraction step 2
- When a muscle is stimulated by a neurone to contract, calcium ions are released from the sarcoplasmic reticulum. Calcium ions bind to the troponin which causes the tropomyosin to move away from the binding site of the actin molecule
Muscle contraction step 3
- Myosin head binds to the actin binding site using ADP
Muscle contraction step 4
When the myosin head is bound it changes its angle and ADP is released.
Muscle contraction step 5
- ATP binds to the myosin head to break the cross bridge between myosin head and actin binding site. Once ATP is used up it becomes ADP which means the myosin head can now bind to a different binding site along the actin
Cycle is repeated
Muscle contraction (sarcomere contracts) steps
- Actin filaments have binding sites for myosin heads but tropomyosin blocks the binding site and it’s held in place by the protein troponin
- When a muscle is stimulated by a neurone to contract, calcium ions are released from the sarcoplasmic reticulum. Calcium ions bind to the troponin which causes the tropomyosin to move away from the binding site of the actin molecule
- Myosin head binds to the actin binding site using ADP
- When the myosin head is bound it changes its angle and ADP is released.
- ATP binds to the myosin head to break the cross bridge between myosin head and actin binding site. Once ATP is used up it becomes ADP which means the myosin head can now bind to a different binding site along the actin
- Cycle is repeated
Sarcoplasmic reticulum surrounds what and what does it do
surround T-tubules
* Contains many Ca2+ ions
* At rest, Ca2+ is actively pumped into the sarcoplasmic reticulum via a Ca2+ pump against a concentration gradient
T-tubules have been depolarised
Voltage gated Ca2+ channels open
Influx of Ca2+ from the sarcoplasmic reticulum into the myofibrils
How does sarcomere contraction affect it’s looks?
i band (light band) becomes shorter and h zone becomes narrower
Neuronal junction
Synapse
What happens at the synapse
- action potential = calcium ions diffuse into neurones
- acetylcholine vesicles fuse w presynaptic membrane (Exocytosis) + diffuses across neuromuscular junction + binds to complementary receptor proteins on sarcolemma
- stimulates ion channels in sarcolemma to open = causes sodium ions to diffuse in = causes muscle to depolarise
- action potential created + travels down t tubules
- causes voltage gated calcium ion channel proteins in the membranes of sarcoplasmic reticulum to open + calcium ions diffuse out + into sarcoplasm surrounding myofibrils
- calcium ions bind to troponin molecules + stimulate shape change
When does muscle contraction stop
- when there’s no more calcium ions bc they’re pumped back into the sarcoplasmic reticulum, once the sarcolemma, t tubules and sarcoplasmic reticulum are no longer polarised
- acetylcholinesterase enzyme in synaptic cleft breaks down acetylcholine molecules
Sarcolemma contracting diagram
Sources of ADP
Aerobic respiration, anaerobic respiration in v active cells (- produces lactic acid which causes muscle fatigue)
- Creatine phosphate (found inside muscles + is a huge store of phosphate groups so it can quickly bind to ADP to form ATP )
Iv
Damage to other endocrine glands could cause similar symptoms
Describe the sequence of actions that occur once adenylyl cyclase is activated in the target liver cells.
- increase sample size to improve accuracy and repeatability of results
- same number of subjects for smokers/non smokers to make comparison more valid
- more repeats before calculating mean to identify anomalies
- other subject factors should be controlled
- smokers and non smokers should’ve been presented as separate columns for easier comparison
- include units for final to columns to show three heart rate measurements made using same method
- label heart rates as mean heart rates for clarity
- cells able to tolerate high levels of lactate
- use of stored ATP
- high Creatine phosphate stores
Skeletal muscle is one of the main tissues where glucose is removed from the blood in response to insulin.
Name the other tissue.
Liver
