Homeostatis and Response Flashcards
Which word means a change in the environment?
Stimulus
Give two examples of effectors
Muscles or glands
Which sense organ has receptors sensitive to light?
The Eye
Which two sense organs has receptors sensitive to chemicals?
The Nose and Tongue
What three conditions are controlled by homeostatis in the body?
Blood glucose concentration
Body temperature
Water levels
What is included in the central nervous system(CNS)?
Brain and spinal cord
A person accidentaly touches a hot pan. Her hand automatically moves away. Describe the structures in a reflex action.
A receptor detects a stimulus.
A sensory neurone transmits impulse to CNS
A relay neurone in the CNS passes the impulse on.
A motor neurone is stimulated.
The motor neurone passes the impulse on to an effector.
Action is taken (the response).
What is the generalised order during a nervous response?
Stimulus –> receptor –> coordinator –> effector –> response –>
Name the three different types of neurones.
Sensory,relay and motor neurones
What moves across the synapse?
A chemical messenger
What is a synapse?
A tiny gap at the junction between two nerve cells.
What three parts are contained in the brain?
Cerebral cortex, cerebellum amd medulla
Describe the three main parts of the brain.
Cerebral cortex- memory and thought
Cerebellum- movement
Medulla- heartbeat and thinking.
What part of the eye controls the amount of light entering it?
Iris
Why does the pupil get smaller?
It is a reflex response and stops damage to the retina.
Why do hormones take so long to act?
They have to travel through the bloodstream
What system releases hormones?
Endocrine system
Which gland is located at the base of the neck?
The thyroid gland
How can Type 2 diabetes be caused?
Lack of exercise and poor diet
Why do hormones last for such a long time?
They have an effect until they are broken down
Which hormones are produces in the male and female reproductive organs?
Testosterone and oestrogen
Is glucagon released by the pancreas when the blood sugar is too high?
Glucagon is not released when the blood sugar is high. Glucagon causes glycogen to be converted to glucose, which increases blood sugar.
How does the pituitary gland affect thyroxine levels?
If the level is too low, it releases Thyroid Stimulating Hormone (TSH). This makes the thyroid gland produce thyroxine.
Why is glucose needed for respiration?
Glucose is a reactant needed for the process
What is homeostatis?
Homeostasis is the control of a constant internal environment for a range of different factors.
Why do the hairs on our skin sometimes stand up when we are cold?
To trap air under them in order to keep us warmer
Which part of the brain monitors body temperature?
Hypothamulus
What happens during vasodilation?
Blood vessels widen so more blood flows through capillaries in the skin
By what process does water move?
Osmosis
Why does sweat help to cool us down?
Sweat removes thermal energy from the skin during evaporation. It does not stay on your skin.
Why are proteins needed in a balanced diet?
Proteins are needed for growth and repair of new and damaged cells. Fibre helps prevent constipation.
Which organ is involved in water regulation in the body?
The kidney
Why is kidney dialysis used?
To clean the blood of patients’ whose kidneys aren’t working properly
How does ADH help control water levels in the body?
ADH affects the permeability of the kidney tubules. The hypothalamus detects internal changes in the body.
Where are receptor cells found?
In sense organs such as: eye, ear, nose, tongue and skin
What is a sensory neurone?
Carries impulses from receptors to the CNS
What is a motor neurone?
Carries impulses from the CNS to the effectors
What is a relay neurone?
Relay neurone connects sensory neurones to motor neurones.
