Nerves and Hormones Flashcards
What is the function of the pituitary gland?
Stores and releases hormones that regulate many bodily functions.
State the function of the cerebrum.
Controls complex behaviour such as learning, behaviour, conscious thoughts, personality and memory.
State the function of the medulla.
Controls automatic bodily functions such as breathing and heart rate.
State the function of the hypothalamus.
Regulates temperature and water balance.
State the function of the cerebellum.
Controls posture, balance and involuntary movements.
State the function of sensory neurones.
Carry electrical impulses from the receptor cells to the CNS.
What is the CNS?
It is made up of the brain and spinal cord.
What is the peripheral nervous system?
All of the neurones that connect the CNS to the rest of the body.
Give the 3 functions of the kidney.
To filter blood, 300 times a day.
Main organ in homeostasis.
To remove excess water, urea and other waste from the blood.
What is a nephron? What does it do?
The filtering part of the kidney. The nephron filters all small molecules out of the blood and then reabsorbed all useful substances by selective reabsorption. Anything left in the nephron becomes urine and is sent to the bladder for storage.
Define:
Hypertonic
Hypotonic
Isotonic
Hypertonic - contains high levels of glucose and salts
Hypotonic - contain low levels of glucose and salts
Isotonic - contain ion concentrations equal to those in blood plasma.
What triggers the thirst response?
A reduction in the water potential of your blood plasma, or an increase in salt concentration.
When are relay neurones used?
In reflexes. They carry electrical impulses from the sensory neurones to the motor neurones, bypassing the CNS.
Where do motor neurones carry signals to and from?
From relay neurones (in reflexes) and the CNS to effectors.
What is the purpose of the myelin sheath? Where is it found?
It is a fatty white substance that surrounds the axon of some neurons (nerve cells), forming an insulating layer. As it is insulating, it will protect nerve cells from the electrical impulses whilst also allowing those electrical impulses to pass through the neurones very quickly.
Define the synapse.
The gap between two neurones. Nerve impulse is transmitted across by neurotransmitters.
What is the axon?
It is a long extension of cytoplasm in neurons that conducts nerve impulse away from the cell body.
Give the order of the reflex arc.
Stimulus - Receptor - Sensory neuron - Relay neuron - Motor neuron - Effector - Muscle
What are receptors?
They are specialised cells that are able to detect changes in the environment and convert stimuli into electrical energy.
What are stimuli?
Anything that can trigger a physical or behavioural change.
Describe how electrical impulses are transmitted across neurones.
The connection in between two neurones is a gap called the synapse. When an electrical impulse reaches the synapse, it stimulates the release of neurotransmitter chemicals that diffuse across the gap and bind to receptors on the next neurone, which triggers a new electrical response.
Define a reflex.
Automatic responses to certain stimuli. Their function is to protect the body.
What is the function of the retina?
The part of the eye that changes light into electrical signals.
What is the purpose of the iris?
It controls the size of the pupil, a hole that allows light into the eye.