Topic 5 - Homeostasis Flashcards
What is homeostasis?
The regulations of conditions inside a body or cell
Why is homeostasis important?
To maintain optimum conditions in response to an internal or external conditions
What three things does homeostasis control?
-blood glucose concentration
-temperature
-water levels
What is a receptor?
A cell which detects a stimuli
What is an effector?
Muscles or glands, which bring about responses which
restore optimum levels.
What is the point of the nervous system?
The nervous system enables humans to react to their surroundings and
to coordinate their behaviour.
Name two parts of the central nervous system
-spinal cord
-brain
How are messages passed through the nervous system?
Via. electrical impulses
What is the reflex arc in order
Stimuli, receptor, sensory neurone, synapse, relay neurone, synapse, motor neurone, effector, response
What is a reflex action?
Automatic and rapid actions which do not involve the conscious part of the brain.
What is a synapse?
The gap between two neurones where messages are sent by chemical diffusion
Why are reflex actions important?
To avoid damage to the cells
Why do synapses slow down a reflex action?
Chemical diffusion is slower than electrical impulses
What is the brain made up of?
Millions of interconnected neurones
What are the three main parts of the brain?
-Cerebral cortex
-Cerebellum
-Medulla
What is the function of the cerebral cortex?
conscious thought
What is the function of the cerebellum?
balance and movement
What is the function of the medulla?
unconscious activities such as breathing, heart rate.
Why is investigating brain function and treating brain damage and disease problematic?
The complexity and delicacy of the brain makes investigating and treating brain disorders very difficult.
What is the function of the retina?
retina- detects light
What is the function of the optic nerve?
optic nerve- carries electrical impulses to the CNS
What is the function of the cornea?
cornea- refracts (bends) light as it enters the eye
What is the function of the sclera?
sclera- outer layer protects the eye
What is the function of the iris?
iris- controls how much light enters the eye
What is the function of the ciliary muscles?
ciliary muscles- contract or relax to control focusing
What is the function of the suspensory ligaments?
suspensory ligaments- connect cliliary muscle to the lens
what part of the body controls and monitors temperature?
The thermoregulatory centre in the brain
where are temperature receptors located in the body?
In the skin
What 2 things happen when body temperatures are too high
Vasodialation and sweating
What 3 things happen when body temperatures are too low?
Vasoconstriction, shivering and hairs standing on end.
How are messages passed on in the human endocrine system?
Through hormones in the bloodstream
What are the six glands and the hormone they produce?
Pituitary gland - many hormones
Thyroid - Thyroxin
Adrenal - Adrenaline
Pancreas - insulin
Ovaries - oestrogen
Testes - testosterone
Which is faster the endocrine or the nervous system?
The nervous system as electrical impulses travel much faster
What is accommodation?
How the eye can adjust to focus on things at different distances
How do we focus on objects at far distances?
The ciliary muscles relax
How do we focus on objects at close distances?
The ciliary muscles contract