Homeostasis + Response Flashcards
What is homeostasis?
the regulation of internal conditions of a cell or organism to maintain optimal body conditions for function in response to a stimuli
What are 3 examples of things homeostasis maintains?
- blood glucose levels
- water levels
- body temperature
Name the two automatic response systems
- endocrine system - Chemical responses
- nervous system - nervous responses
What does the nervous system consist of?
- the central nervous system (CNS)
- the peripheral nervous system
What do the nerves in the peripheral nervous system do?
nerve cells that transfers information to or from the CNS
What does the CNS consist of?
the brain and the spinal cord
What are the 3 control centers?
- receptors
- coordination centers
- effectors
What do receptors do?
detect stimuli (change in environment)
what occurs in the coordination center?
organs such and your brain, pancreas and spinal cord receives and processes informations from the receptors
What do effectors do?
they carry out tasks from the coordination center to maintain optimum conditions
Give two examples of effectors
- muscles
- glands
What are nerves?
a bundle of neurons
What do nerve cells do?
they have adapted to carry electrical impulses from one place to another
What are the three main types of neurons?
- sensory
- motor
- relay
How does information from the receptor travel?
they travel along neurons as an electrical impulse to coordinators e.g CNS
In the nervous system what is the order that information flows from receptors to effectors?
stimulus, receptor, coordinator, effector, response
Name 5 times of receptors
- skin
- nose
- ear
- eye
- tongue
How do can muscles or a gland work as an effector?
- muscles can contract to move
- glands can release hormones
What are reflex actions?
actions that do not involve the conscious part of the brains and so are much quicker
What is a reflex arc?
the nerve pathway followed by a reflex action
Describe the seven steps in a reflex arc
- stimulus
- receptor
- sensory neuron
- relay neuron
- motor neuron
- effector
- response
What does a sensory neuron do?
sends electrical impulses to the relay neuron
What does the relay neuron do?
they connect sensory neurons to motor neurons
What do motor neurons do?
they send electrical impulses to the effectors
Describe fully how information move along neurons
an electrical impulse causes a chemical impulse called a neurotransmitter to move across the synaps. The neurotransmitters then bind to the receptors on the second neuron and triggers an electrical impulse
What does the brain do?
the brain controls complex behaviors
What does the brain do?
the brain controls complex behaviors
What are the four main areas of the brain?
- cerebral cortex
- cerebellum
- hypothalamus
- medulla
What functions do the cerebral cortex control?
intelligence
personality
conscious thoughts
high level functions
What does the medulla control?
unconscious activity
What does the hypothalamus control?
maintaining body temp + water levels
What does the cerebellum control?
balance and muscular activity
How have neurosurgeons been able to understand what regions of the brain controls which function
- studying patients with brain damage
- electrically stimulating different parts
- using MRI scanning techniques
Name 2 non-invasive procedures that help neurosurgeons study the brain
- electrical stimulation
- MRI brain scans
Describe how electrical stimulation helps describe brain activity
scientists send weak electrical currents to stimulate parts of the brain and ask the patient to describe what happened
What happens if a motor area is stimulated by the electric current
the patient makes an involuntary movement
What happens if a visual area is stimulated by the electric current
the patient will see a flash of colour
What are the functions of EEG’s
they can be created and studied to observe the electrical activity in the brain
How does an MRI work?
the use strong magnetic fields and radio waves to show details of the brain’s structure and function
How can MRI’s locate specific parts of the brain used to carry out specific tasks?
patients are asked to perform specific tasks and by looking at the scan scientists can locate the active parts of the brain when the task is carried out
Name 3 things that can negatively impact the brain
- tumors
- trama
- infections
Why is it physically difficult to fix issues in the brain
its surrounded by the skull and also very fragile brain tissue
Why is it difficult to fix problems with drugs/chemicals
we do not fully understand all the functions of the brain due to how complex it is
What is the eye?
a sense organ contain receptor that react to change in light intensity and colour
Name the six structures in the eye
- coernia
- iris
- pupil
- lense
- retina
- optic nerve
What does the cornea do?
it refracts the light that’s hits it
What does the iris do?
controls the size of the pupil
Name 2 adaptations the cornea has to work well
- its transparent to allow light to refract
- it has oxygen diffuse through the surface as it has no blood vessels
What is the purpose of the iris reflex
allows the optimum amount of light to pass through the pupil
Why does your pupil shrink when faced with high light intensity?
high light intensity damages the retina
Why does your pupil grow in low light settings
to allow more light to be refracted to the retina
When your pupils shrink in the light they are …?
constricted
When your pupils grow in the dark they are …?
dilated
What are the names of the two muscles in the iris?
- circula muscle
- radial muscle
How do the circular muscle and the radial muscle act to constrict the pupil?
the circular muscle contracts and the radial muscle relaxes
How do the circular muscle and the radial muscle act to dilate the pupil?
The circular muscle relaxes and the radial muscle constricts
Where is the lense located?
behind the pupil
What does the lense do?
refracts the light, changes the shape of the image and focuses the light on the retina
Name the 2 receptor cells in the retina
- cone cells
- rod cells
what is a cone cell sensitive to?
colour
What is a rod cell sensitive to?
light - cannot detect colour
What is the fovea?
a spot on the retina that only consists of cone cells and where all the light refracted should be focused on to create a clear image
What does the optic nerve do?
transfers any impulses from the receptor cells and transmits them to the brain
What is accommodation?
a reflex that controls the refractive power of the lense
When an object is close up how do the light rays act, how much do they need to be refracted?
they hit the eye at a wide angle and therefor need to be refracted a lot
When an object is far away how do the light rays act, how much do they need to be refracted?
they hit the eye and are almost parallel meaning they do not need to be refracted much
What is the structure of the lense to allow it to refract light rays a lot?
short and fat
What is the structure of the lense to allow it to refract light rays a little?
tall and thin
What are the two muscles/ligaments that allows the lense to change shape?
- ciliary muscle
- suspensory ligament
How does the ciliary muscle and suspensory ligament act to allow the lense to be short and fat?
the ciliary muscle contracts inwards which slackens the suspensory ligaments stopping them from pulling on the lense allowing it to become short and fat
How does the ciliary muscle and suspensory ligament act to allow the lense to be tall and thin?
the ciliary muscle relaxes which causes the suspensory ligaments to become taut making them pull on the lense allowing it to become tall and thin
What is thermoregulation?
the regulation of body temperature
What is the optimum body temperature?
37
What happens to the enzymes if the body temperature falls?
they slow down
What happens to the enzymes if the temperature rises?
they can denature
Where is the thermoregulatory center?
in the hypothalamus in the brain
Name 2 receptors that detect a change in temperature
- skin
- blood vessels
Name 3 mechanisms the body has to warm up
- shivering
- vasocontraction (constricting the blood vessels)
- contracting the erector muscles (traps insulating air by making your hair stand up on end)
How does shivering raise the body temperature?
when shivering you are automatically contracting your muscles this requires energy that come from respiration which produces heat energy
Name 3 mechanisms the body has to cool down
- sweating
- vascodialation (expanding blood vessels)
- relaxing the erector muscles
What does the endocrine system consist of?
glands that are all around the body
What do glands do?
secrete hormones
How do hormones travel around the body?
through the bloodstream
How do hormones trigger changes in the body?
when travelling through the bloodstream they come in contact with many tissues, specific tissues will then have receptors that the hormones can bind to the hormones then act as signals and trigger responses from the tissue
Name 6 Glands
pituitary gland
thyroid gland
adrenal gland
pancreas
testis
ovaries
Where is the pituitary gland found?
connected to the brain but not part of it
What do the hormones that the pituitary gland releases do?
either tell the body what do to do or travel through the bloodstream and tell other glands to secrete hormones
Where is the Thyroid gland?
in the neck
Which hormone does the thyroid gland release?
thyroxine
What does the hormone thyroxine do in the body?
regulates the rate of the metabolism and helps with growth + development
If there is a low level of thyroxine in the body what will the pituitary gland do?
secretes a the hormone TSH (thyroid stimulating hormone)
Where are the adrenal glands located
on top of the kidneys
Which hormone do the adrenal glands secrete
adrenalin
When is adrenalin normally produced?
during fight or flight mode
What happens when the hormone adrenalin is produced?
an increase in heart rate and a more efficient breathing rate
Which hormone does the pancreas produce?
insulin
Where is the pancreas located?
in front of the kidneys
What does the hormone that the pancreas secretes do?
regulates blood glucose levels
What hormone does the testis secrete?
testosterone - only found in men
What does testosterone do around the body?
controls puberty and produces the male gamete, sperm
What hormone do the ovaries produce?
oestrogen - only found in women
What does oestrogen do around the body?
produces the female gamete, the egg
controls the menstrual cycle
controls puberty
Name the difference between the endocrine system and the nervous system
the endocrine system takes longer to go into effect but is long lasting whereas the nervous system moves faster with shorter lasting effects
the endocrine system relies on hormones travelling through the blood while the nervous system relies on electrical impulses travelling between nerve cells
the endocrine system travels all round the body leading the affect to be more general where as the nervous system is more precise
What does blood glucose concentration refer to?
the amount of glucose (sugar) in our bloodstreams
Why do we need glucose in our bloodstream?
so our cells have a constant supply for respiration
What is glycogen?
a large molecule of repeating glucose molecules
What is glucagon?
a hormone that rises the blood glucose levels
How does the body react when glucose levels are too high?
when levels are too high the pancreas will release insulin which travels through he bloodstream and binds to liver and muscle cells which then sign al for the cells to absorb more glucose they then use the glucose molecules to form glycogen which is easier to store and this brings your blood glucose levels down
How does the body react when glucose levels are too low?
the pancreas will release glucagon which is a hormone that will bind to the liver and muscle cells in your bloodstream when they have done this they act as signals which tell the cellos to convert the glycogen inside them back into glucose and release it into the bloodstream which allows the blood glucose levels to rise again
What happens to your body if you have type 1 diabetes?
your body produces little to no insulin
What happens to your body if you have type 2 diabetes
your cells become resistant to insulin due to you blood glucose levels always being high
In who is type one diabetes more likely to be developed?
in children and teenagers
What happens is you blood glucose levels get too high and cant be regualted?
the person affected can become really sick and in worse conditions can die
What is the treatment for type one diabetes?
injecting the individual with insulin in their thigh or abdomen after eating
What are people with diabetes recommended to do?
consume small amounts of sugar
exercise frequently
In who is type two diabetes more likely to be developed?
in older people with unhealthy lifestyles
what are the main jobs of the kidney?
filter blood
remove blood from the kidneys
what is urea?
