The Structure And Function Of The Nervous System Flashcards
Nervous system
Complex network of 10^11 cells
- specializes for reception, transmission, processing and generation of information
Two main divisions of nervous system
1) CNS - central nervous system
—> brain and spinal cord
2) PNS - peripheral nervous system
—> sensory & motor nerve fibres that extend from the CNS to other areas of the body
What is the nervous system made up of?
Neurons and supporting neuroglia/ glial cells
Neuron consists of:
- Cell body
- Dendrites
- Axon
- Synaptic terminals
Neuron cell bodies often aggregate in:
1) Grey matter of CNS
- Ganglia or Nuclei [compact groups]
- laminae [sheets]
2) PNS
- specialized ganglia
Nerve fibres consist of:
- Dendrites or axons [cytoplasmic processes extending from the cell body]
- Schwann cells [neurilemma and surrounding endoneurial sheath]
Where are nerve fibres found?
- white matter of CNS
- sling peripheral nerve tracts
Flow diagram of the passage of a nerve impulse from the taste bud to the areas of the brain in which taste is perceived:
- TASTE BUD
- MICROVILLI ON RECEPTOR CELLS
- AFFERENT SENSORY NERVE FIBRE
- MEDULLA
- THALAMUS
- PRIMARY GUSTATORY CORTEX
Structure of grey matter
- neuron cell bodies
- dendrites
- unmyelinated axons
- glia
- synapses and capillaries
Function of grey matter
- Connects CNS to other parts of the body
- Point at which axon receives impulses from other sensory neurons
- Motor neurons responsible for muscle contractions
- Glial cells provide support, nourishment and structure to nerve cells
Structure of white matter
- longe range myelinated axons
- dendrites
Function of white matter
- Connects grey matter areas and carries impulses between them
- Point at which axons receive impulses
Peripheral nerve structure
- afferent neurons
- efferent neurons
- cell bodies
- dendrites
- axons
- Schwann cells
- myelin sheath
- axon hillock
Peripheral nerve function
- Sensory nerves that bring impulses towards CNS
- Motor neurons carrying impulses away from CNS to muscles
- Point at which axons receive impulses from sensory neurons
- Schwann cells are specialized cells that make myelin sheath
- Myelin sheath is a layer that provides protection, insulation and a speeds transmission of signals
AFFERENT neuron
A neuron conducting impulses to the brain or spinal cord
- carries nerve impulses from receptors towards the CNS
Axon
Long, thread-like part of nerve cell along which impulses are conducted from the cell body to other cells
Axon (nerve) terminal
Enlarged, club-shaped endings in which axons make synaptic contact with other nerve cells or effector cells
Axon hillock
Specialized part of the cell body of a neuron that connects to the axon
- tapery region between a neuron’s cell body and it’s axon
Cell body
The soma, the part of a neuron containing the nucleus but not incorporating the axon and dendrites
Central canal (spinal cord)
The cerebrospinal fluid filled space that runs longitudinally through the lengthy of the entire spinal cord
Dendrites
Short, branches extension of a nerve cell along which impulses received from other cells at synapses are transmitted to the cell body
Dorsal
On or relating to the upper side of back of animal, plant or organ
Dorsal (posterior) horn
A longitudinal subdivision of grey matter in the dorsal part of each lateral half of the spinal cord that received several types of sensory info from the body
Dorsal fissure
A kind narrow opening
- any cleft or grove, especially a deep fold in the cerebral cortex involving its entire thickness
Dorsal root
One of the 2 roots of a spinal nerve that passes posteriorly to the spinal cord separating the posterior and lateral horn
Effector
An organs or cell that acts in response to a stimulus
Efferent neuron
Motor neuron
- carry nerve impulses away fro the central nervous system for effectors
Endoneurial sheath (endoneurium)
Outermost later of delicate connective tissue around the myelin sheath
Epineurial sheath (epineurium)
Outermost layer of dense irregular connective tissue surrounding a peripheral nerve
Epithelial cells
One or several cells arranged in one or more layers that form part of a covering or lining of a body surface
Grey matter
The darker tissue or the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites
Interneuron
A neuron that transmits impulses between other neurons, especially as part of the reflex arc
Muscle
A band or bundle of fibrous tissue inside a human or animal body that has the ability to contract, producing movement or maintaining the position of part of the body
Nerve (neuron)
A fibre or bundle of fibres in the body that transmits impulses of sensation to the brain or the spinal cord & impulses from these to the muscles and organs
Neurilemma (Schwann cells)
A cell that forms spinal layers around a myelinated nerve fibre between two nodes of Ranvier
Neuroglia/ glial cells
Non-neuronal cells that maintain homeostasis from myelin, provide support, protection for neurons in the brain and PNS
Neuromuscular junction
Connects the nervous system to the muscular system via synapses between efferent nerve fibres and muscle fibres
Node of Ranvier
A gap in the myelin sheath of a nerve between adjacent Schwann cells
Taste bud
Any of the clusters of bulbous nerve endings on the tongue in the lining of the mouth which provide the sense of taste
Taste pore
The minute opening of a taste bud on the surface of the oral mucosa through which the gustatory hairs of the specialized neuroepithelial gustatory cells project
Transduction
A process of converting energy from a chemical stimulus into an electrical impulse by a receptor cell
Ventral (anterior) toot
On of the two roots of a spinal nerve that passes anteriorly from the spinal cord, separating the anterior and posterior funiculi, and that consists of motor fibres
Ventral fissure
Ventral groove that divides the spinal cord into lobes
Ventral horn
The front column of grey matter in the spinal cord
White matter
The polar tissue in the brain and spinal cord, consisting mainly of nerve fibres with their myelin sheaths
