Homeostasis & Response Flashcards
Fight or flight response:
What are the 2 changes in a human body caused by adrenaline?
Increased oxygen to muscles and brain.
Increased glucose to muscles and brain.
What is the hypothalamus and which 2 things does it detect?
Part of the brain that detects changes in blood temperature/ water concentration.
True or false: Adrenaline is controlled by negative feedback.
False.
Low thyroxine levels in the bloodstream stimulate the _______________ to release ______,
causing the ___________________ to release ______ to stimulate the thyroid gland into releasing ___________________.
So blood levels return to __________.
hypothalamus
TRH
pituitary gland
TSH
more thyroxine
normal
Normal thyroxine levels in the bloodstream ___________________ from the ___________________.
This inhibits the release of _______ from the __________________, so normal blood levels are maintained.
inhibit TRH release
hypothalamus
TSH
pituitary gland
Explain how the body regulates the amount of thyroxine that is produced if the body is not stressed or cold. (Negative feedback) (2)
Once a certain amount of thyroxine is produced,
thyroxine __________ the __________________ from _____________ the thyroid gland,
so _______ thyroxine is produced.
inhibits
pituitary gland
stimulating
less
Cold weather stimulates the __________________,
which stimulates the ________________ to produce more ______________.
The increase of thyroxine raises the _____________________.
Which increases ______________________, and then increases ____________________.
pituitary gland
thyroid gland
thyroxine
basal metabolic rate
rate of respiration
body temperature
Explain how stressful situations can cause people to gain weight. (3)
There is less _______________ of thyroid gland, so ________________ is produced.
So basal metabolic rate ________________.
Therefore reduced __________________, so more ______________________.
stimulation
less thyroxine
decreases
respiration rate
food is stored as fat
What is homeostasis?
Maintaining a constant internal environment for optimum conditions for cell function.
The kidneys regulate ___________________.
The skin regulates _____________.
The liver and pancreas regulate ______________.
water and mineral ion concentration.
body temperature.
blood-glucose levels.
How does the body carry out homeostasis for body temperature?
Get rid of excess heat when hot.
Retain heat when cold.
What are the 3 examples of coordination centres?
Brain
Spinal cord
Pancreas
True or false: The endocrine system detects our surroundings and responds to stimuli.
False. The nervous system detects our surroundings and responds to stimuli.
Communication:
The nervous system uses ________________.
The endocrine system uses ________________.
electrical impulses
hormones
A hormone is a ___________________.
That produces a ____________________.
chemical messenger
chemical change
The endocrine system is made up of _________________ that secrete ______________________.
endocrine glands
hormones directly into the bloodstream
In nervous control, the effectors are ________________________.
In hormonal control, effectors are ________________________.
muscles or glands
target cells in specific tissues
The nervous system is ______ acting.
The endocrine system is _____ acting.
fast
slow
What is the function of the ADH (anti-diuretic hormone)?
Controlling the water content of blood in the kidneys.
Where is ADH secreted from?
The pituitary gland.
Why is it important to maintain the right blood-glucose concentration?
Because cells need glucose for _________, and blood glucose concentration affects the _______________________.
energy
blood’s water potential
Why is it important to keep your internal environment constant?
Because it is vital for cells to function normally and stop them from being damaged.
Why is it important to maintain core body temperature and blood pH?
Because body temperature and pH affect ___________________, and enzymes affect the _______________________________.
enzyme activity
rate of metabolic reactions
Why does the rate of metabolic reactions increase when temperature increases?
Because more heat means more kinetic energy,
so the molecules move faster.
What is the order of a control system?
- Receptor.
- Coordination centre.
- Effector
What is the central nervous system made up of?
The brain and spinal cord.
What is the peripheral nervous system?
Neurons that carry information to and from the central nervous system.
What is the function of an effector?
To produce a response.
What are 2 examples of effectors?
Muscle and glands.
A bundle of neurones is called a __________.
nerve
What are the functions of receptors in the skin?
They detect stimuli and convert the information into impulses.
Receptors stimulate _________________ in response to stimuli.
electrical impulses
What are the adaptations of neurones?
Long axon
Branching dendrites
Myelin sheath
What are the functions of the adaptations of the neurones:
long axon,
branching dendrites
and myelin sheath?
Long axon- To carry electrical impulses from one part of the body to another.
Branching dendrites- To communicate with other neurones.
Myelin sheath- To speed up and insulate the electrical impulses.
A car driver sees a traffic light went red, describe the action of the nervous system: (4 marks)
______________ are receptors to the stimulus: the red light.
An electrical impulse is sent to the _____. ( The coordination centre).
The brain sends an electrical impulse to the effectors: ___________.
The foot muscles produce a response by the muscles moving to __________.
Retinal cells in the eye
brain
the foot muscles
put on break
What are the functions of neurotransmitters?
Neurotransmitters diffuse across the synapse and bind to receptor sites.
An _________________ travels along the __________________.
Triggering the nerve-ending of the neurone to release ______________________.
These chemicals _________________________ and bind with the __________________ on the second neurone.
The receptor site only binds to __________ neurotransmitters released from the first neurone.
Stimulating the second neurone to __________________________.
electrical impulse
first axon
neurotransmitters
diffuse across the synapse
receptor site
specific
transmit an electrical impulse
What is the difference between a reflex action and a voluntary action?
In a reflex action, instead of a coordination centre a relay neuron receives and processes information.
What is the sequence of a reflex action?
1.
2.
3.
4.
5.
6.
7.
Stimulus
Receptor
Sensory neurone
Relay neurone
Motor neurone
Effector
Response
What is a reflex arc?
A nerve pathway followed by a reflex action.
A car driver automatically brakes if a child dashes out into the road. This is a _______ action.
reflex
How can an anatoxin lead to death? (3 marks)
If the anatoxin ___________________ it triggers an ____________ in the neurone.
If the anatoxin remains bound, the neurone will _____________________ to the muscle.
If it affects the ______________, it will ________________________, leading to the stop of breathing.
binds to the receptor
impulse
continually send impulses
diaphragm
continually contract
If the glucose level is too high, the brain stimulates the pancreas to __________.
Insulin stimulates the liver to convert ________________.
Glycogen is ______ in the _____.
release insulin
glucose into glycogen
stored
liver
What is the function of insulin?
Converts glucose into glycogen for storage to lower blood-glucose levels.
What is Type 1 Diabetes?
A disorder in which the pancreas fails to produce enough insulin.
How can people with Type 1 Diabetes control their blood glucose levels?
- Eating foods that will not cause ________________________________.
- Exercising because it increases the rate of __________________________.
large increases in blood glucose levels
respiration in the muscles
_______________ happens when the the glucose level is too low.
The brain stimulates the pancreas to release _________.
Glucagon stimulates the liver to convert __________________.
So glucose can be released into the ____________.
Negative feedback
glucagon
glycogen back to glucose
bloodstream
A woman has an artificial pancreas. Describe what happens to bring the blood glucose levels to normal:
(4 marks)
The rise in blood glucose levels is ___________________.
Information is used to _________ how much ________ she is going to need to bring her blood glucose levels back to normal.
_________ insulin to the blood.
Causing glucose to _____________.
detected by the sensor
calculate
insulin
A pump delivers
move into cells
How do some diabetics change insulin levels?
Before a large meal, glucose levels increase.
While undertaking exercise, glucose levels decrease.
What happens on days 1-4 in the menstrual cycle?
Menstruation. The uterus lining breaks down.
What happens on days 5-13 in the menstrual cycle?
Uterus lining is repaired.
What happens on day 14 in the menstrual cycle?
Ovulation. An egg is released from the follicle.
What happens on days 15-28 in the menstrual cycle?
Uterus lining is maintained.
What is the function of FSH and the gland it is released from?
FSH is released from the pituitary gland, it matures the egg inside of the follicle.
It stimulates the release of oestrogen.
What is the function of Oestrogen and the gland it is released from?
Oestrogen is released from the ovaries.
Oestrogen repairs the uterus lining and stimulates LH.
What is the function of LH and the gland it is released from?
LH is released from the pituitary gland.
It causes ovulation.
And stimulates progesterone.
What is the function of Progesterone and the gland it is released from?
Progesterone is released from the ovaries.
It maintains the uterus lining.
And inhibits FSH and LH.
Describe how the mature eggs are used in IVF treatment so that the woman may become pregnant
(3 marks)
Eggs are ___________.
To form ____________.
Then the embryo is ___________ into the mother’s _________.
fertilised
embryos
inserted
uterus
Which 2 hormones do female oral contraceptive pills contain and why?
Progesterone and oestrogen to inhibit FSH and LH so the egg does not mature and is not released from the follicle.
What is the order of stages during IVF treatment?
- Stimulate follicles.
- Extract eggs from ovaries.
- Collect sperm.
- In vitro fertilisation.
- Implantation.
What 2 hormones is the mother given during IVF treatment?
FSH and LH.
