Central nervous system Flashcards
(33 cards)
What is the central nervous system made up of?
- Brain
- Spinal cord
What is the peripheral nervous system made up of?
- Somatic nervous system (motor and sensory)
- Autonomic nervous system
Functions of the CNS?
- Bring in sensory info from inside and outside
- Deliver motor commands out to muscles of the body.
- Intelligence, memory, learning and emotion.
What cells are found in the neural tissue?
- Neurons; send and receive signals.
- Neuroglia; support and protect neurons.
Functions of the PNS?
- Deliver sensory information in to the CNS.
- Carry motor commands out to peripheral tissues and systems.
What are nerves?
- Sensory or motor nerves, meaning they carry sensory or motor info.
- Cranial nerves = connect to brain.
- Spinal nerves = attach to spinal cord.
Describe the difference between afferent and efferent?
- Afferent division carries sensory info from PNS to CNS.
- Efferent division carries motor commands from CNS to PNS muscles and glands.
What is the difference between receptors and effectors?
- Receptors detect changes in neurones, complex sensory organs.
- Effectors respond to efferent signals, cells and organs.
Name the 3 types of neurones?
- Unipolar neurones.
- Bipolar neurones.
- Multi polar neurones.
Describe unipolar neurones?
- Very long axons
- Fused dendrites and axon
- Cell body to one side
Describe bipolar neurones?
- Small
- One dendrite, one axon
Describe multi polar neurones?
- Very long axons
- Multiple dendrites, one axon
What are the functions of sensory neurons?
- Monitor internal environment of the body.
- Respond to the effects of external environment.
What are inter-neurones?
- Transmits impulses between other neurones.
- Located in brain, spinal cord and autonomic ganglia.
- Responsible for sensory info and coordination of motor activity.
- Involved in higher functions, e.g. memory, planning, learning.
Name the four types of neuroglia in the CNS?
- Ependymal cells; contact neuroglia directly.
- Astrocytes; large cell bodies.
- Olgiodendrocytes; smaller cell bodies.
- Microglia; smallest, with least number of neuroglia.
What does the cell body of neurones consist of?
- Large nucleus
- Nucleolus
- Major organelles, e.g. mitochondria, golgi
What does the dendrites of a neurone consist of?
- Short, highly branched projections from cell body.
- Function = receive info from other neurones.
What do axons of neurones consist of?
- Long cylinder, transmit impulses.
- Synaptic terminals are the tips of axons.
What happens during nerve impulse conduction?
- Impulse starts in the nerve cell.
- Passes along the axon.
- Gets to the axon terminal.
- And passes onto next nerve cell or muscle or gland.
How fast are nerve impulses?
Varies from 0.1-100 per sec. Speed affected by: -Temp -Axon diameter -Myelin sheath makes impulse quicker.
Describe a myelin sheath?
- Surrounds neurone.
- Gated channels; nodes of ranvier.
- Action potential jumps from node to node = saltatory conduction.
Describe a synapse?
- Junction between 2 neurones where the action potential cannot cross the gap (synaptic cleft).
- Impulse carried by a neurotransmitters.
Describe the stages of transmission of action potentials.
- An action potential arrives at presynaptic neuron, depolarizes it.
- Calcium ions enter synaptic knob, triggers release of Acetyl choline.
- ACh travels across synaptic cleft and binds to receptors, depolarizes postsynaptic membrane.
- ACh enzymes breaks ACh into acetate and choline.
Name 5 important neurotransmitters?
- Acetyl choline
- Norepinephrine (NE)
- Dopamine
- Serotonin
- Gamma aminobutyric acid
