Topic 5 – Homeostasis and Response Flashcards
What is homeostasis?
Homeostasis describes all of the processes that happen in a cell or organism to maintain (keep) optimal conditions. This is needed to respond to changes in the internal and external environment.
What is the function of the nervous system?
it enables organisms to react to their surroundings and coordinates behaviour
Why are reflex actions described as rapid and automatic?
they do not involve the conscious part of the brain
What are the two parts of the central nervous system?
brain and spinal cord
Why are reflex actions important?
for survival and to prevent damage to the body
Give the pathway of the cerebral cortex.
outer layer of the brain playing an important role in consciousness
Give the function of the medulla oblongata
part of the brain above the spinal cord that controls breathing and heart rate
Give the function of the cerebellum
part at the back of the brain involved in coordinating muscle activity
Why is it difficult to treat brain disorders?
the brain is very complex and delicate
What is a synapse?
gap between two neurones, allowing impulses to cross
What is the function of neurones?
Carry electrical impulses around the body
Give three internal conditions controlled in homeostasis.
body temperature, blood glucose and water levels
Give three things all control systems include
receptors, coordination centres and effectors
What is accommodation?
Process of changing the shape of the lens to focus on near/distant objects
Give two common defects of the eyes.
Myopia(short-sightedness)and hyperopia(long-sightedness)
How can eye defects be treated?
spectacle lenses, contact lenses, laser surgery, and replacement lenses in the eye
Where is body temperature monitored and controlled?
thermoregulatory centre in the brain
What happens if body temperature is too high?
blood vessels dilate(vasodilation) and sweat is produced
What happens if body temperature is too low?
blood vessels constrict(vasoconstriction), sweating stops, and shivering takes place
What is the endocrine system?
system of glands that secrete hormones into the bloodstream
How do the effects of the endocrine system compare to those of the nervous system?
endocrine system effects are slower but act for longer
Where is the pituitary gland located?
brain
Which organ monitors and controls blood glucose?
pancreas
Which hormones interact to regulate blood concentration?
insulin and glucagon
What is the cause type 1 diabetes?
pancreas produces insufficient insulin
What is the cause of type 2 diabetes?
body cells no longer respond to insulin
What is the function of the kidneys?
filter and reabsorb useful substances from the blood, and produce urine to excrete excess water, ions and urea
How are excess amino acids excreted from the body?
deaminated to form ammonia in the liver, ammonia is converted to urea and excreted
Which hormone controls the water level in the body?
ADH
How is kidney failure treated?
organ transplant or kidney dialysis
What is the function of FSH?
causes eggs to mature in ovaries, and stimulates ovaries to produce oestrogen
What is the function of LH?
stimulates the release of an egg
What is the of oestrogen?
causes lining of uterus wall to thicken
What are the methods of hormonal contraception?
oral contraceptives, an injection, implant, or skin patch
State the disadvantages of IVF treatment
- emotionally and physically stressful
- low success rate
-can lead to risky multiple births
What is the function of adrenaline in the body?
increase heart rate and boosts delivery of oxygen and glucose to brain and muscles to prepare the body for ‘fight or flight’
What is the function function of thyroxine in the body?
stimulates basal metabolic rate, so is important for growth and development
What is geotropism?
orientation and growth of plants in response to gravity
What is phototropism?
orientation and growth of plant in response to light
What are the uses of gibberellins in agriculture?
end seed dormancy, promote flowering, and increase fruit size
