Homeostasis and response Flashcards
Fill in the gaps:
Homeostasis is the ___________ of ________ conditions to maintain ________ conditions for ___________ activity and cell ____________.
-regulation
-internal
-optimal
-enzyme
-functions
What things need to be regulated in our body? (name 4)
-temperature
-blood glucose levels
-water levels
-ion content
What is the central nervous system made up of?
brain and spinal cord
What is the peripheral nervous system made up of?
the nerves that branch out from the brain and spinal cord to the rest of the body
Fill in the gaps:
a bundle of neurons is called a _____
nerve
How is a neuron adapted to its function? (3 ways)
-long fibre axon so they can carry messages up and down the body over long distances
- insulating fatty myelin sheath increases the speed of nerve impulses along the neuron
- dendrons and dendrite branches recieve many nerve impulses from other neurons.
What is the function of a sensory neuron?
takes information from the receptor to the central nervous system
What is the function of the motor neuron?
takes information from the central nervouse system to the effector
Fill in the blank:
When the electrical impulses reach the nerve ending it stimulates the release of chemicals called ___________________.
these diffuse across the _________ and bind to receptors on the surface of the second neuron.
an electrical triggered in the second neuron passes down the _____
-neurotransmitters
- synapse
-axon
What is thermoregulation?
the proccess of controlling body temperature
Fill in the blank:
Temperature is regulateed by the ________________ _________ in the brain (______________)
- thermoregulatory centre
- hypothalamus
Body temperature is detected by:
- receptors in the thermoregulatory centre detect temperature of blood
- temperature receptors in the skin
Name the steps of a conscious response
1, change in environment (stimulus)
2. change detected by receptor cells
3. impulses sent along the sensory neuron to the central nervous system
4. central nervous system decides how to respond to this information (co-ordinator)
5. impulses sent down the motor neuron to the effector (muscle or gland)
6. effector brings about the response to the stimuli
What is the function of the retina?
contains light receptors
What is the function of the cornea?
refracts light, bends it as it enters the eye
What is the function of the iris?
controls how much light enters the pupil
What is the function of the lens?
Further refracts light to focus it onto the retina
What is the function of the sclera?
tought white outer layer of the eye helps to protect the eye from injury
What is the function of the opric nerve?
Carries impulses between the eye and the brain
What is the function of the pupil?
small hole at the centre of the iris through which light enters the eye
What is the function of the ciliary muscles?
controls the shape of the lens to help focus on an image
What is the function of the suspensory ligament?
holds the lens in place
Fill in the blank:
In dim light the muscles in the iris ______ to make the pupil __________ so that more light can enter the eye. in bright light, the muscles ____________ to make the pupil ________ so that less light can enter the eye.
- relax
- larger
- contract
- smaller
What is the proccess of accomodation?
the proccess by which the lens changes shape in order to focus on an object
What is long sightedness also known as?
hypermetropia
What is short sightedness also known as?
myopia
How can long sightedness be corrected?
a convex lens causes the light to be refracted more ensuring the image is focused on the retina rather than behind it
How can short sightedness be corrected?
concave lens which causes light to be refracted less so that the image is focussed on the image rather than ahead of it
What is the medulla responsible for (brain)
unconscious activities such as heart rate and breathing rate
what is the cerebral cortex responsible for (brain)
concerned with intelligence, personality, conscious thoughts, memory and language
what is the cerebellum responsible for (brain)
balance, co-ordination of movement and muscular activity
What is the hypothalamus responsible for? (brain)
near the pituitary gland, helps regulate the body including water levels, temperature and appetite
How have neuroscientists been able to discover parts of the brain and its functions? (3 ways)
- studying patients with brain damage and corelating the area damaged to the skill or function lost
- electrically stimulating different parts of the brain and seeing what happens
- using scanning techniques such as MRI or PET scans
Fill in the blanks:
The endocrine system is made up of a collection of _______ which release _______________ to bring about a response to a stimulus.
- glands
- hormones
what are hormones?
chemical messengers that travel around the body in the blood
What hormone does the pituitary gland release?
ADH
What does ADH do? and what does it target ?
controls the water content of the blood by increasing reabsorption of water by the collecting ducts (targets kidneys)
to look at near objects the cilliary muscles ________ which slackens the _______ ligaments
the lens becomes ___
this increases the amount by which it ______ light
contract
suspensory
fat
refracts
to look at distant objects , the ciliary muscles _____ which allows the suspensory ligaments to _____ tight
this make the lens go ____
relax
pull
thin
