Nervous tissue Flashcards
wk 6
What are the three functions of nervous system?
sensory, integrative and motor
describe sensory function of the nervous system.
Receptors detect internal stimuli or external stimuli
Information carried to brain and pinal cord via cranial and spinal nerves
Describe integrative function of the nervous system.
Process information by analysing and making decision about appropriate response= integration
What is the impact of the effector on muscles and glands?
Stimulation of effecter causes muscles to contract and glands to secrete.
Describe the motor function of the nervous system.
After integration: system elicits an appropriate response by activating effectors (muscles and glands)
Though cranial and spinal nerves
What is the input to the CNS from periphery called?
afferent division
what is afferent division stimulated by?
sensory and visceral stimuli
What are the three components of a neuron?
cell body, dendrite and axon
what is the function of the neuron?
are specialised communication cells
What are the two synaptic neurons?
Presynaptic and posy-synaptic
What does a presynaptic neuron do?
sends nerve impulses towards another cell
what does a postsynaptic neuron do?
receives a nerve impulse and responds to it.
What are the three structural types of neurons?
Multipolar, bipolar and unipolar
Where are multipolar neurons found?
Mostly in brain and spinal cord
What are two multipolar neurons and their purpose?
Motor neurons - take action potentials away from CNS
Interneurons (most)
In-between sensory and motor
Where are bipolar neurons found?
in the ear and retina
What are uniploar neurons and what is their function?
sensory receptors: take sensory information towards the CNS
What are the 4 types of Glial cells?
Astrocytes, oligodendrocytes, microglia and ependymal cells
what is the largest and most common cell of the CNS?
Astrocyte
what are the functions of astrocytes?
support neurons
Assist in forming blood brain barrier
Help maintain correct chemical environment
What are Glial cells
Non neuronal cells in the CNS and peripheral nervous system
Don’t produce electrical impulses
what is the function of Oligodendrocytes?
Form and maintain myelin sheath around axons
what are microglia and their purpose?
phagocytes
Remove cellular waste and debris
what structural features do ependymal cells have?
microvilli and cilia
What is the function of epidenymal cells?
produce spinal fluid and assist in moving it around
What is the structure of the blood brain barrier?
endothelial cells of capillaries and astrocytes held together by tight junctions
what are the two functions of the blood brain barrier?
Protects
-brain cells from substances and pathogens
Selective barrier
-prevent passage of substances into brain blood
What is the function of Shawn cells?
Form and maintain myelin sheath
Involved in axon regeneration
in PNS
what are the two functions of satellite cells?
Supports neurons
Regulate flow of materials into cell bodies
Where do satellite cells reside and what are they a precursor to?
Between external lamina and sarcolemma
Precursor to skeletal muscle cells
What does myelination allow for?
This insulates the axons and speed
What is grey matter?
Collection of neuronal cell bodies
What is white matter and why?
Bundles of axons (give a white appearance when myelinated)
Where is the spinal cord? Why?
Inside vertebral column
This allows for protection and support