Module 5: Animal responses Flashcards
How is the nervous system organsised
Split into central and peripheral nervous system
Central: Brain and spinal cord
Peripheral: somatic and autonomic
autonomic: parasympathetic and sympathetic
What does the somatic nervous system do
- conscious control (running etc)
- skeletal muscles
What does the autonmic nervous system do
controls unconscious activities
like heart rate, breathing, digestion
What does the parasymapthetic nervous system do
rest and digest
What does the symapthetic nervous system do
Fight or flight
What are the different parts of the brain
Cerebrum Hypothalamus Medulla oblongata Cerebellum Pituraity gland
What function does the cerebrum have
controls:
voluntary actions
personality
learning, hearing and thinking
What function does the cerebellum do
Coordinates muscle movement
particularly balance and posture
What function does the medulla obolongata have
autonomic control
Controls heart rate, breathing rate
What function does the hypothalamaus have
Automatically maintains body temperature
monitors blood glucose level, water levels
Sympathetic nervous system
produces hormones that control the pituitary gland
What function does the pituitary gland have
Split into anterior (produces hormones like FSH) and posterior glands (stores hormones made by hypothalamus like ADH)
Releases hormones to stimulate other glands
What is a reflex action
an action where the body respsonds to stimulas without making a concious decison
Explain how the blinking reflex works
Stimulas: something touches the eye
Receptors: an impulse is sent along sensory neurone to CNS
CNS: passed from relay neurone to motor neurone
Effector: motor neuones send impulses to muslces that move your eyelid
Response: msucles contract (obicularis oculi) causing eyelids to cloe quickly (prevents damage)
Explain the knee jerk reflex
Stimulas: detects quadracepst has been streched
Receptors: strech receptors in quadriceps muscles detect that muscle is being streched, then impusle passed along sensory neurone
CNS: sensory neurone communicates with motor neurone in spinal cord
Effectors: motor neurone carries impulse to quadriceps
Response: quadriceps muscle contarcts so lower legs move forwards
Describe the flight or fight response (ACTH)
Hypothalamus also releases a peptide hormone that stimulates the anterior pituitary gland to release ACTH
ATCH is transported to the adrenal glands through the bloodstream
Causes adrenal cortex to secrete the hormone cortisol
Cortisol stimulates target organs and tissues to increase blood pressure, blood glucose ensuring the tissues have sufficient glucose and oxygen needed for rapid response
Cortisol also suppresses the immune system
Describe fight or flight response (adrenaline)
- Heart rate increases
- Muscles around bronchioles relax, causing airways to widen
- intercoastal muslces and diaphragm contract faster
- Glycogen is converted to glucose
- erector pilli muscles contract
What part of the nervous system triggers the fight or flight response
hypothalamus activates hormonal system and sympathetic nervous system
What is the receptor called that detects high or low blood pressure
Barorecpetor
What is the receptor called that detects changes in co2 concentration and pH
Chemoreceptors
Describe how heart rate is controlled when there is a high blood pressure
- barcoreceptors in aorta and cartoriod atery detect high bp
- impulse sent via sesnory neruone to cardiovascular centre
- impulse sent along parasympathetic neurone
- these secrete acetycholine which binds to recpetors on SAN (sinoatrial node)
- heart rate slows, bp back to normal
Describe how heart rate is controlled when there is a low blood pressure
- baroreceptors in the aorta and cartoriod artery detect low bp
- impulse sent via sesnory neruone to cardiovascular centre
- impulse sent along sympathetic neurone
- these secrete noradrenaline which binds to recpetors on SAN (sinoatrial node)
- heart rate speeds up, bp back to normal
Describe what happens when there is a high blood pH levels or low co2, and high o2
- chemoreceptors in aorta, carotid arteries and medulla oblongta detect chemical change
- impulse sent along sensory neurone to the cardiovascular centre
- impulse sent along parasympathetic nerve
- acetylcholine is secreted which binds to SAN (sino atrial node)
- causes heart rate to decrease
- so oxygen, carbon dioxide and pH levels back to normal
Describe what happens when there is a low blood pH levels or high co2, and low o2
- chemoreceptors in aorta, carotid arteries and medulla oblongta detect pH change
- impulse sent along sensory neurone to the cardiovascular centre
- impulse sent along sympathetic nerve
- noradrenaline is secreted which binds to SAN (sinoatrial node)
- causes heart rate to increase
- so oxygen, carbon dioxide and pH levels back to normal
What other hormone can bind onto receptors to cause the cardiac muscle to contract more frequently
Adrenaline
