Biology (needs to move) Flashcards
What is the peripheral nervous system and what parts is it divided into
peripheral nervous system- All the nerves outside the CNS and its function is to relay information to and from the CNS from the body
- somatic nervous system
- autonomic nervous system
What is the somatic and autonomic nervous system
somatic = voluntary actions and external senses e.g. touch, sight and hearing
autonomic - Involuntary actions e.g. heartrate, breathing, blood pressure, digestion etc
What 2 branches is the autonomic nervous system split into
Sympathetic - involved in the preparation of the flight or fight response. it raises your heartrate, bronchioles are dilated, pupils dilate, digestion is inhibited, bladder relaxes
parasympathetic - After sympathetic returns the body to its ‘normal’ resting state. Heartrate decreases, bronchioles are constricted, pupils constrict, bladder contracts
What is the function of a - sensory
- relay
- motor neuron
sensory - Detects the stimuli and carry’s the impulses to the CNS from the sensory receptor
relay - it allows the sensory and motor neuron communicate
motor - carries the impulse to the muscles (effectors) to contract or relax depending on the stimuli
What is the difference between the structure of the neurons
relay - no myelin sheath
sensory - cell body and nucleus in the middle of the axon
motor - cell body at the end of the neuron
what is the functions of the:
Axon
dendrites
cell body
myelin sheath
. Axon - carriers impulses away from the cell body
. dendrite = receives the electrical impulses
. cell body - control centre of the neuron
. myelin sheath - speeds up electrical impulse
Where abouts on the neuron is the
- Axon
- myelin sheath
- dendrites
- cell body
and what do they look like
. Axon - long line between dendrites
. dendrites - branches on both ends of the neuron
. cell body - contains a nucleus ( sensory-axon, motor-end of neuron)
. myelin sheath - on the axon
What is the proccess of synaptic transmission
- An action potential (electrical impulse) travels along the axon of the pre-synaptic neuron towards the axon terminal
- This action potential triggers the nerve ending of the pre-synaptic neuron to release chemical messengers called neurotransmitters from vesicles into the synapse
- The neurotransmitters diffuse across the synapse
- The neurotransmitters bind to specific receptors on the membrane of post-synaptic neurons
- A new action potential is triggered if enough excitatory neurotransmitters are received by the post-synaptic neuron
- The neurotransmitters are then re absorbed by the pre-synaptic neurons called uptake
what are excitatory neurotransmitters
on switches
increases the likelihood of an excitatory signal being sent to the post-synaptic cell, which is then most likely to fire
e.g. dopamine
What are inhibitory neurotransmitters
off switches
- decreases the likelihood of neurons firing
- responsible for calming the mind and body and inducing sleep
e.g. serotonin
What are the primary functions of the endocrine system
produce and release hormones and regulate bodily functions
what are the key functions of the endocrine system
. growth and development- Hormones like growth hormones influence physical growth and organ development
. metabolism- hormones such as thyroxine control energy usage
. reproduction - Hormones such as oestrogen and testosterone are involved in sexual development and reproduction
. Stress - Adrenaline and cortisol prepare the body for fight or flight
. Mood and Sleep regulation - melatonin and serotonin influence sleep-wake cycles and mood
How do the hormones know which cells to effect
The cells have complimentary receptors that match the hormones chemical structure
What are the main glands and their hormones and functions
. pituitary - master gland - controls other glands
. Adrenal - cortisol and adrenaline - manages stress response by increasing heartrate (fight or flight)
. thyroid - thyroxine -regulates metabolism- affects heartrate and temperature
. pancreas - insulin and glucagon - controls blood glucose levels
. ovaries - oestrogen and progesterone - female sexual tendency’s
. testes - testosterone - male sexual tendency’s
. pineal - melatonin- regulates sleep-wake cycle
what are the definitions for
- hormone
- gland
- homeostasis
Hormone - produced by glands, acting as a messenger to regulate body functions
Gland - synthesises and releases hormones into the bloodstream
Homeostasis - the body’s ability to maintain a stable internal environment
What is the flight or flight response
survival mechanism for when the body prepares for a perceived threat or stress it is designed to increase an organism’s chance of survival by enabling quick physical action
what are the key components of the fight or flight response and how do you get it
nervous system and endocrine system
its a natural function
What is the acute stress pathway called in the fight or flight response and what is its function
SAM (immediate response)
- Hypothalamus activates the autonomic nervous system on the sympathetic branch
- Activates the Adrenal medulla which releases adrenaline and noradrenaline into the blood stream
- increases heartrate and oxygen and glucose to the muscles and suppresses non essential processes such as digestion
What does adrenaline and noradrenalin do
adrenaline - increases heart rate, dilates air passages and redirects blood flow to essential organs
noradrenaline - increases focus, heartrate, and blood flow to the muscles; boosts oxygen supply to the brain
What is the chronic stress pathway called in the fight or flight response and what is the function
(HPA) - longer term response
- hypothalamus releases CRF into the blood stream which activates the pituitary gland
- The pituitary gland releases ACTH which activates the adrenal cortex
- this then releases cortisol
what does cortisol do in the flight or flight response
Increases glucose production for energy and suppresses the immune system
it can lead to high blood pressure and a weakened immune system
What does the parasympathetic immune system do
After the fight or flight response it brings the body back to normal levels
