homeostatis Flashcards
Define homeostasis
maintaining a constant internal conditions inside the body in response to internal or external changes
What is the nervous system?
a network of nerve cells and fibres which transmits nerve impulses between parts of the body
What is the endocrive system?
a collection of glands that produce hormones that regulate metabolism, growth, sexual function, sleep, reproduction, mood etc.
What are the nervous system components?
brain, spinal cord, nerves
What is a stimulus?
A change in your enviournment which you need to react to, for example light, sound touch, pain, pressure etc.
What do sensory neurones do?
carry signals from receptors to the brain
What do relay neurones do?
carry messages from one part of the CNS to another
What do motor neurones do?
carry signals from CNS to effectors
What is the central nervous system?
CNS= brain and spinal cord
What is the peripheral nervous system?
PNS= nerves
What are sense organs?
receptors that detect stimal: eyes, nose, ears etc.
What is the Synapse?
the tiny gap between 2 meeting neurones
What are the main stages of a reflex arc?
stimulus->receptor->sensory neuron->relay neuron->motor neuron-> effector->response.
What is the optic nerve function?
connects and sends messages from the eye to the brain
What is the cornea function?
allows light rays enter the eye
What is the iris function?
Contrasts size of the pupil, helping regulate entry
What is the pupil function?
allows light to pass through the iris
What is the ciliary muscle function?
alters the thickness of the lens through contraction
What is the sclera function?
protects the delicate parts of the inside of the eye
What is the suspensory ligaments function?
hold the lens in position and alters its shape
What is the retinas function?
contains light sensitive cells
What is the blind spot function?
point at which optic nerve leaves the eye.
How is the temperature of the body monitored?
controlled by the thermoregulatory centre, skin has temperature receptors
What is the thermoregulatory centre?
contained in the hypothalamus in the brain, contains receptors sensitive to the temperature of the blood
How does the body respond if body temperature becomes too high?
Vasodilation, sweat production, which both transfer energy from skin to the environment, resulting in a cooling effect.
How does the body respond if the body temperature is too low?
Vasoconstriction, and shivering (involuntary contraction and relaxation of muscles which releases energy from glucose) starts
What happens to excess protein in a diet?
The excess amino acids produced from digesting proteins are transported to the liver from the small intestine
how does the kidneys function to maintain water balance in the body?
Producing urine. The urine is taken from the kidneys to the bladder by the ureters. The bladder stores the urine until it is convenient to expel it from the body.
2 ways kidney failure can be treated
Kidney dialysis (Medical treatment in which blood is removed from the body and filtered before being returned) or organ transplant
response of plants to light
phototropism
response of plants to gravity
geotropism
3 ways auxins are used in agriculture and horticulture
as weed killers.
as rooting powders.
for promoting growth in tissue culture.
role of ethene in plants
controls cell division during plant growth.
how is ethene used in the food industry?
to speed up the ripening process, after fruits have been transported
what can ethene cause in plants
shedding of leaves