14. Co-ordination and Response Flashcards
Define
Synapse
The junction between two neurones
Define
Hormone
A chemical substance,
produced by a gland and carried by the blood,
which alters the activity of one or more specific
target organs
Where is glucagon secreted?
Pancreas
Where is adrenaline secreted?
Adrenal glands
Where is insuline secreted?
Pancreas
Where is testosterone secreted?
Testes
Where is Oestrogen secreted?
Ovaries
Define
Adrenaline
and its effects
the hormone secreted in
‘fight or flight’ situations and its effects,
(a) increased breathing rate
(b) increased heart rate
(c) increased pupil diameter
How does adrenaline affect metabolic activity?
a) increasing the blood glucose concentration
(b) increasing heart rate
Define
Homeostasis
The maintenance of a
constant internal environment
What function does Insulin serve?
It decreases blood glucose
concentration
Define
Vasodialation
Sphincter muscle relaxes to allow more blood to go to the surface capillaries for heat loss
Define
Vasoconstriction
Sphincter muscle contract to allow less blood to go to the surface capillaries for heat loss
3 marks
What does the skin do to regulate body temperature in a cold environment?
- Vasoconstriction
- Less sweat secreted from the sweat glands
- Hair erector muscles contract so hair rises
4 marks
What does the skin do to regulate body temperature in a hot environment?
- Vasodialation
- More sweat secreted from the sweat glands
- Hair erector muscles relax so the hair lays flat
- Muscles cause shivering (involuntary contractions)
Name the three layers of skin
Epidermis
Dermis
Adipose tissue
5 marks
Examples of Homeostasis?
- Body temperature
- Water potential
- Blood pH
- Oxygen/Carbon dioxide concentration
- Glucose concentration level in blood
Importance of Homeostasis?
- Optimum temperature for enzymes
- So that cells do not gain too much water by osmosis and burst
Treatment for Type 1 Diabetes
- Regular monitoring of blood glucose level
- Injecting Insulin
- Diet - reduced intake of sugars (eat slow release carbs eg starch)
- Exercise - regular aerobic exercise
What does the CNS constist of ?
Central Nervous System
Brain and the Spinal cord
What does the PNS consist of?
peripheral nervous system
Nerves outside of the brain
and spinal cord
Define
Reflex action
A means of
automatically and rapidly integrating and
coordinating stimuli with the responses of
effectors (muscles and glands)
Define
Effectors
Muscles or glands that bring about a response
What carries our coordination and response?
The Nervous System
The Endocrine System
Why is coordination and response needed?
- To respond to stimuli in your environment
- To maintain a constant internal environment (homeostasis)
Name the types of neurones and their connections
- Sensory neurone - from the sense organ to the CNS
- Relay neurone - Sensory nerve to the motor neurone
- Motor neurone (in the CNS) - Relay neurone/CNS to the effector
Describe how an impulse travels
reacting to the stimuli of heat or a pin
Stimulus is detected by the receptor (skin), sensory neurone send impulses to the spinal cord (the coordinator), impulse travels through the relay neurone to the motor neurone, to the effector (muscle), effector carries out a response (musle contracts to pull arm up)
Describe reflex actions
Automatic
Rapid response
Protective - minimise damage to the body
What is the function of the synapse?
To ensure that an impulse travels in one direction only
6 marks
Explain how an impulse moves across the synapse
- An electrical impulse arrives through the presynaptic neurone
- This intiates the vesicles containing neurotansmitters to fuse with the membrane and and release neurotransmitters into the synapse
- Neurotransmitter diffuse across the synapse/synaptic gap
- Neurotransmitter bind to the protein receptors, on the post synaptic nerve, with specific complementary shapes to theirs.
- This intiates a nerve impulse in the post synaptic nerve.
neurotransmitters are destroyed after to prevent continued stimulation o
Sense organs and what they sense
- Eyes - Light
- Skin - Temperature, Pain, Pressure, Touch
- Nose - Chemicals in the air
- Tongue - Chemicals in food and drinks
- Ear - Sounds and Acceleration
Define
Sense organ
Groups of receptor cells
responding to specific stimuli
What is the function of the cornea?
Refracts light
What is the function of the Iris
Controls how much light enters the
pupil
What is the function of the Lens?
Focuses light on to the retina
What is the function of the Retina?
Contains light receptors, some
sensitive to light of different colours
rods and cones
What is the function of the optic nerve?
Carries impulses to the brain
How does the iris control the size of the pupils?
The circular and radial muscles work antagonistically.
When in bright light, circular muscles contact
When in a dim environment, radial muscles contract
This is to protect the retina
