Biology Paper 2

Created by

Hannah McIntrye

Cards (219)

What is homeostasis?
Homeostasis is the regulation of the internal conditions of a cell or organism in response to internal or external changes to the enviroment.
Why is homeostasis important?
Because it keeps conditions constant for enzyme action and cell functions.
What does homeostasis include the control of? [3]
- Blood glucose concentration - Body temperature - Water and ion levels
What may control systems involve? [2]
- Responses using nerves - Chemical responses using hormones
What is a receptor cell?
It detects a stimuli
What is a stimuli?
A change to the enviroment
Give examples of coordination centres? [3]
- Brain - Spinal cord - Pancreas
What do coordination centres do?
Receive and process information from the receptors
What do effectors do?
They bring about responses that restore optimum levels
What are examples of effectors? [2]
- Muscles - Glands
What happens in negative feedback? [3]
- A receptor detects a change in a stimulus - The coordinating centre commpares the stimulus to a set point - An effector then produces a response to correct any difference from the set point
What does the nervous system enable humans to do?
Enables them to react to their surroundings and coordinate their behaviour
Where does information from the receptors pass to?
Passes to the central nervous system.
What does the CNS coordinate?
It coordinates the response of effectors.
What are reflex actions like?
Automatic and rapid so they can protect the body
Explain the nervous system
Stimula --> Receptor --> Sensory Neurones --> Relay Neurones --> CNS --> Relay Neurones --> Moto Neurones --> Effector --> Response
How do neurones communicate with each other?
Via synapses
What is the electrical impulse name that when it reaches the synapse and has to diffuse across the gap to the other synapse?
Neurotransmitters
What is the endocrine system?
It is made up of glands that secrete hormones directly into the bloodstream.
What are hormones?
Hormones are chemical messengers that are carried in the blood to a target organ or tissue.
Compared with the effects of the nervous system, are the effect of hormones longer?
Yes, they are also slower.
What is the pituitary gland?
It is the 'master gland'. - It secretes several hormones in response to body conditions.
Where is adrenaline produced?
In the adrenal glands
What does adrenaline do to your body?
It increases heart rate, boosting the delivery of oxygen and glucose to the brain and muscles.
What does adrenaline prepare your body or?
Flight or fight
Where is Thyroxine produced?
In the Thyroid gland
What does Thyroxine regulate? [3]
- Rate of metabolism - Heart rate - Temperature
Where is testosterone produced?
Testes
What does testosterone do?
Controls puberty and sperm production in males.
Where is oestrogen produced?
In the ovaries
What does oestrogen do?
It is involved in the menstrual cycle
What monitors and control the blood glucose concentration?
Pancreas
What happens if the blood glucose is too high? [3]
- Pancreas releases more of the hormone insulin - Insulin is transported to the liver, where it binds with liver cells and causes the glucose to move into the liver cells. - Excess glucose is converted into glycogen for storage
What hormone is secreted by the pancreas if the blood glucose concentration is too high?
Insulin
What hormone is secreted by the pancreas if the blood glucose concentration is too low?
Glucagon
What happens if the blood glucose concentration is too low? [2]
- Pancreas releases glucagon - Glucagon stimulates glycogen to be converted into glucose and released into the blood
What is Type 1 diabetes caused?
- It is caused by the pancreas failing to produce enough insulin
What does Type 1 diabetes result in?
High blood glucose levels
How is type 1 diabetes treated?
By insulin injections
What is Type 2 diabetes caused by?
It is caused by the body cells no longer responding to insulin