B9.1 - Nervous control in humans Flashcards
what are the systems involved in coordination and response in humans?
nervous system and hormonal (endocrine) system
what is the nervous system?
its a system involved in coordination and response in humans. it includes the brain, the spinal cord, the peripheral nerves and specialised sense organs.
what is stimulus mean?
a change in condition
what do you need for a coordinated response to occur?
receptor organ and effector
what is the hormonal (endocrine) system?
its a system involved in coordination and response in humans. it uses chemical communication by means of hormones.
Name four human nervous system.
CNS, PNS, Receptor organs and effectors
what is the CNS?
the brain and spinal cord which processes nervous impulses from the body and coordinates any response.
what is the PNS?
all the nerves in the body that connects the CNS to other parts of the body.
what is a receptor organ?
a bunch of receptors is a sense organ, it responses to a specific stimuli.
what is a effector?
it produces the response , such as the contraction of muscles and the secretion of hormones from glands.
what is a bundle of neurones?
a nerve
how is the sense organs connected to the CNS?
nerves connect them together
what is an special adaptation for a neurone?
it has many endings that connect with other neurones to pass on electrical impulses
what are the three types of neurones?
sensory neurones, relay neurones, motor neurones.
what does a sensory neurone do?
it carries impulses from sense organs to the CNS (brain or spinal cord).
what does a relay neurone do?
its found inside the CNS and it connects the sensory neurone to the motor neurones
what does a motor neurone do?
it carries impulses from the CNS to effectors (such as muscles or glands)
what does neurones have?
Axons and Dendrons
Describe and explain what a Axon is.
- its a long fibre which is insulated by a fatty sheath. this allows the impulse to travel quickly.
- Schwann cells form myelin sheath around axons.
Describe and explain what a Dendron/dendrite is.
its tiny branches (dendrons) which branch further as dendrites at each end. this makes it easier to respond to the stimulus and pick up the impulses from many other neurones.
Describe a sensory Neurone
its long and have a cell body branching off the middle of the axon
Describe a relay neurone
its short and have a small cell body at one end with many dendrites branching off it.
Describe a motor neurone
its long and have a large cell body at one end with long dendrites branching off it.
what is the simplest type of response to a stimulus?
a reflex response
what type of voluntary is a reflex response?
involuntary
whats the pathway that impulses travel along during a reflex response called?
a reflex arc
what the reflex arc pathway?
Stimulus –> receptor –> sensory neurone –> relay neurone in CNS (pass message to brain) –> motor neurone –> effector –> response
is the simple reflex a spinal reflex or a reflex that involves that brain?
spinal reflex
what is a spinal reflex?
its a impulse processed by the spinal cord, not the brain.
is no impulse sent to the brain during a spinal reflex?
no, its still sent so the brain knows what happening. however the brain is not involved in this action.
what does it mean to override a reflex response?
for example if your holding a large bowl of hot food , you might look around to find somewhere to put it down rather than dropping it straight away.
what is a involuntary response (or reflex) ?
it doesnt involve the brain as the coordinator of the reaction.
what is a voluntary response?
its where you make a conscious decision to carry out a particular action, so it starts with your brain.
