B5 Flashcards
Define homeostasis
the maintenance of a stable internal environment
Why does homeostasis need to maintain optimal conditions?
- so enzymes + cells don’t denature
- and for enzyme + cell to functions
List three conditions that the body needs to maintain
- blood glucose concentration (bgc)
- temperature
- water
What do the two automatic response systems involve?
- nervous response
- chemical response
What does receptor do?
detects a stimuli
What is a stimuli?
an environmental change
List the receptor cells and state what stimulus they detect
- skin detects : touch, pressure, pain & temperature
- nose detects : chemicals in the air
- tongue detects : chemicals in food
- ears detects : change in sound
- eyes detects : changes in light and color
What does a coordination center do?
receives and process the stimuli from a receptor
Name the 3 coordination centers in the body and describe what each of them coordinates
- brain = coordinates information from the receptor cells and send signals to the muscles and glands
- spinal cord = coordinates messages from the brain ,receptor cells and coordinates reflexes
- pancreas = coordinates the glucose levels in the blood
What is an effector and an example?
carries out responses to stimuli - either a muscle or gland
- example: muscles contracting to lift a leg
Define the nervous system
it enables humans to react to their surrounding and to coordinates their behavior
Describes what happens at the nervous system
- a stimulus (environmental change )
- these are detected by receptors and information passes along cells (called neurones)
- as electrical impulses to the CNS
Name the two parts of the central nervous system
- brain
- spinal cord
What does the CNS coordinate?
coordinates the response of an effector which may be muscle contracting or glands secreting hormones
Put these in the correct order: receptor, stimulus, response, coordinator, effector
stimulus 🡪 receptor 🡪 coordinator 🡪 effector 🡪 response
What is the role of the sensory neurone?
carrying electrical impulses from the receptor to the CNS
What is the role of the relay neurone?
connecting the sensory neurone to the motor neurone in the CNS
What is the role of the motor neurone?
carrying electrical impulses from the CNS to an effector
What is a synapse?
the gap between 2 neurones
Describe what happens at the synapse
- when an impulse reaches the end of a neurone a chemical (neurotransmitter) is released across the gap
- the chemical then diffuse across the synapse
- when the chemical reaches the next neurone it starts another impulse
What is a reflex action?
an automatic and rapid action, they don’t involve the conscious part of the brain
Why are reflex actions important?
they protect the body from injury
What is the path that a reflex action takes called?
- reflex arc
Recall the pathway of the reflex arc
receptor 🡪 sensory neurone 🡪spinal cord 🡪 motor neurone 🡪 effector
What does the pancreas do?
- it produce and secretes the hormones(insulin and glycagon)
- monitors and controlled the blood glucose concentration
Name the hormones that the pancreas releases
- insulin
- glycagon
What does insulin and glycagon do to the blood glucose concentration?
the hormones regulates the bgc as insulin reduces the concentration and glycagon increase the concentration of glucose in the blood
What happens to the glucose in the blood when insulin is released?
- when bgc is too high the pancreas release insulin
- the glucose moves from the blood into the cells
- the liver & muscle cells converts the excess glucose into glycogen
Describe the role of glucagon in the regulation of glucose?
- when bgc is too low the pancreas releases glycagon
- and it stimulates the liver & muscle cells
- to convert glycogen into glucose
What is diabetes?
is a conditions that causes a person’s blood glucose level to become too high
Which type of diabetes is caused when the pancreas fails to produce enough insulin?
type 1
What happens when there’s a lack of insulin in type 1?
an uncontrolled high blood glucose level
Which type of diabetes is caused when the body cells no longer respond to insulin?
type 2
What is the 2 main risk factors of type 2?
- obesity
- old age
State how Type 1 diabetes is treated
- insulin therapy - insulin being injected when blood glucose levels are too high
- controlling carbohydrates in the diet
- regular exercise
State how Type 2 diabetes is treated
- controlling carbohydrates in the diet
- regular exercise
What is bgc an example of ?
- an example of negative feedback
- this ensure any control system changes is reversed and returned back to the set level
Explain 3 reasons why its important to control blood glucose level?
- glucose is a fuel for respiration
- if bgl are low = organism cannot meet its energy demand
- if bgl are high = impacts on osmosis by affecting concentration gradients
