Wk.6 L2 - Nervous System (2) Flashcards
LO
- Explain how a neural circuit structure works to sense stimuli from external world (sight, sound, smell, taste, touch, temperature), or from inside the body (visceral pain, blood pressure, body position in space and time…), and then interprets these stimuli resulting in movement, emotion and behaviour.
- Describe how compartmentalisation and organisation of cells in the nervous system, making up distinct anatomical components of the brain, spinal cord and peripheral nervous system, works together to enable sense, movement and behaviour.
NS
made up of neurons and glial cells
Neurons
Signalling units of NS
Excitable cells that connect to other excitable cells (neuron or muscle)
Glia
Support functions of neurons
- Astrocytes (metabolical support & support blood-brain-barrier)
- Oligodendrocytes (makes myelin sheath CNS)
- Microglia (specialised immune cells)
Endothelial cells
Line blood vessels
Form blood-brain-barrier
Human brain
GOB (grey outside brain)
60% white
40% grey
NS function and structure
Sensory receptor:
- Detects change in environment
Sensory system:
- Transfer info to CNS for analysis
Integrating areas of CNS:
- Analyse info broardly and makes desicion on best response
Motor system:
- Delivers info to effector site
Motor Neuron synapse at effector muscle:
- Generates the response at effector site
Primary sensory neuron
Detect and send info via PNS to CNS
- Chemical receptors
- Mechanical receptors (psi/ stretch receptors)
- Thermoreceptors
- Special receptors (taste, light, sound etc.)
CNS structure
Cerebral hemispheres
Diencephalon
Brainstem (midbrain, pons, medulla oblongata)
Cerebellum
Spinal cord
Neurons
- Connect to eachother via synapses
- Conduct e- impulses
- communictae by transmitting chemical signals across synapses
Microanatomy of neuron
Dendrite
Soma (cell body)
Axon
Nucleus
Nucleolus
Granules within Soma
Schwann cells
Nodes of Ranvier
Multipolar or unipolar (pseudo)
Functional classification of neurons
Interneurons:
- Connect other neurons
Lower motor neurons:
- Connect to muscle cells
Primary sensory neurons:
- Have sensory receptors detecting change in the external environment/ inside body
- Often have a cell body in the dorsal root ganglion
Cellular structure of neuron soma
Surrounded by plasma membrane
Nucleus and nucleolus
Nissl bodies (rER & free ribosomes)
Golgi apparatus
Mitochondria
Unipolar neurons
No dendritic processors from soma
Sensory neurons found in peripheral ganglia
- 1 branch to CNS
- 1 branch to periphery
