Coordination - The Eye and Ear Flashcards
(51 cards)
What is a stimulus?
A change in the environment of an organism that produces a response
The sequence of events in the coordination system:
Stimulus ➡ receptor ➡ CNS ➡ effector ➡ response
The function of receptors:
To detect a stimulus by changing the energy they receive into electrical energy in nerve impulses
A nerve cell is called _______
Neurone
How are impulses that travel along the nerve cell caused?
Due to the movement of ions in and out of the neurone
What makes up the CNS?
Brain and spinal cord
Where is the cell body of the sensory neurone located?
Outside the CNS
Where is the cell body of the muscle neurone located?
Inside the CNS
What is a myelin sheath?
Covering made up of lipids (fatty material called myelin) by membranes of specialised cells that surround an axon as it develops
What is its function?
It insulates the axon and prevents short circuits with other axons
Speeds up the conduction of the impulses
Pathway in synapses (integrating info. in CNS):
Pre-synaptic neurone ➡ electrical impulses ➡ neurotransmitters (vesicles) ➡ diffuse ➡ receptors (membranes) ➡ post-synaptic neurone ➡ generate impulses ➡ broken down by enzymes
What are reflex actions?
A reflex action is a rapid and involuntary (not started by impulses from the brain) response to a stimulus
What is a reflex arc?
Nerve pathway of a reflex action
Pathway for a reflex action:
Receptors ➡ sensory neurones ➡ dorsal root ➡ synapse ➡ relay neurone ➡ motor neurone ➡ ventral root ➡ effector
Where are the cell bodies of sensory neurones located in a reflex pathway?
Swelling in the spinal nerve called the dorsal root ganglion
Location of grey matter:
The tissue in the middle of the spinal cord and outer part of the brain
Consists of mainly nerve cell bodies
Location of white matter:
The tissue in the middle of the brain and outer part of the spinal cord
Consists of mainly nerve cell axons
Receptors and effectors for the knee-jerk reflex (acts in situations where the knee joint is unexpectedly flexed eg. helping you to stop from tripping or falling over):
Receptors: stretch receptors in the tendons below the knee
Effectors: thigh muscles (contract)
The largest part of the brain?
Evaluate it
Cerebrum: 2 cerebral hemispheres
: cerebral cortex
Functions of the cerebrum:
- Contains sensory areas
- Motor areas
- Higher activities: memory, emotions, personality
Other parts of the brain (not cerebrum):
Cerebellum
Medulla (cardiac and respiratory center)
Hypothalamus
Pituitary gland
Meninges
The functions of the cerebellum:
- Coordinating the contraction of sets of muscles
- Maintaining balance
Oval window
Membrane covered opening leading from the middle ear to the cochlea in the inner ear
Eustachian tube
Connecting the ear to the throat so that air pressure on both sides of the eardrum is equalised
