coordianation and response- key terms Flashcards
Define central nervous system (CNS)
consists of the brain and spinal cord, which are the areas of coordination.
Define peripheral nervous system (PNS)
comprises nerves and neurones, which coordinate and regulate body functions.
types of neurones: define nerve impulse
an electrical signal that passes along the nerve cells called neurones
types of neurones: define axons
Ensure less time is wasted when the impulse is transferred from one neurone to another
types of neurones: define dendrities
Extensions which form a network for easy communication.
types of neurones: define motor neurone
Carry impulses from the CNS to effectors (muscles or the glands)
types of neurones: define sensory neurone
Carry impulses from the sense organs (sensory receptors) to the CNS.
types of neurones: define relay neurone (Interneurone)
The middleman inside the CNS connects sensory to motor neurones.
Define reflex action
automatically and rapidly integrates and coordinates the stimuli with the responses of effectors (muscles and glands).
Define synapse
a junction between two neurones, consisting of a gap across which impulses pass by diffusion of a neurotransmitter
Define sense organ
groups of receptor cells responding to specific stimuli: light, sound, touch, temperature, and chemicals
Define cornea
refracts light
Define Iris
controls how much light enters the pupil
Define lens
focuses light onto the retina
Define retina
contains light receptors, some sensitive to light of different colours (Rods and cones)
Define optic nerve
carry impulses to the brain
Define pupil
A hole which allows light to enter
Define hormones
A chemical substance produced by a gland and carried by the blood, altering the activity of one or more specific target organs.
Define the hormone and function of Adrenal gland
horomone: Adrenaline
function: Prepares the body for vigorous action
Define the hormone and function of Pancreas
hormone: Insulin
function: Reduces the concentration of glucose in the blood
Define the hormone and function of Testes
hormone: Testosterone
function: Causes the development of male sexual characteristics
Define the hormone and function of Ovary
hormone: Oestrogen
function: Causes the development of female sexual characteristics
Define the hormone and function of Pancreas
hormone: Glucagon
function: Increases concentration of glucose in the blood
Define homeostasis
The maintenance of a constant internal environment.
Define negative feedback
controls the production of hormones and regulates their own production
Define type one diabetes
caused by the death of the cells that secrete insulin.
Define auxin
Plant hormones or growth substances
Controls tropisms
It is produced by cells at the tip of the roots and shoots of plants
Define gravitropism
a response in which a plant grows towards (positive) or away (negative) from gravity.
Define phototropism
a response in which a plant grows towards (positive) or away (negative) from the direction light is coming.
Define insulation
provided by fatty tissue retains heat. Hairs become erect to trap warm air by contracting erector muscles and vice versa.
Define vasodilation
when it is hot, arterioles, which supply blood to the skin-surface capillaries, dilate (become wider) to allow more blood near the skin surface to increase heat loss (face redder)
Define vasoconstriction
when it is cold, arterioles, which supply blood to the skin-surface capillaries, constrict (become smaller) to allow less blood near the skin surface to decrease heat loss
Define sweating
the water evaporates, giving a cooling effect
Define skin receptors
sense heat, and sensory neurons send impulses to the hypothalamus
Define shivering
muscular activity generates heat
Define sweat glands
Producing sweat to regulate heat.
Define thermoregulatory centre
the hypothalamus controls corrective mechanisms (e.g. sweating and shivering).
