Chapter 7 Flashcards
- Define the three specific functions of the nervous system.
- Sensory input -monitor changes in stimuli (sensory receptors)
- Integration - Decides what should be do with it (brain and spinal cord)
- Motor output - response (activating muscles or glands)
Describe the organization of the nervous system, including the structural and functional classifications.
sensory organs > sensory afferent pathway > Peripheral Nervous system > Central nervous sysem (brain and spinal cord) > peripheral nercous system > motor efferent pathway > Somatic (voluntary) muscles or Autonomic organs (smooth or cardiac muscles, glands) > sympathetic or parasympathetic division
What are the different types of neuroglia cells in the CNS and PNS? (6)
Neuroglia - supportive nerve glue protecting neurons
Astrocytes - feed and protect neurons, most abundant
Microglial - defend CNS cells, monitor neuron health
Ependymal - line the brain and spine to make a protective watery cushion with cerebrospinal fluid (CSF)
Oligodendrocytes - produce fatty myolin sheath coverings around nerve fibres
Peripheral Nervous System:
Satellite - act as protective, cushioning cells for peripheral neuron cell bodies similar to ependymal cells
Schwann cells - form the myelin
sheaths around nerve fibers in the PNS similar to oligodendrocytes
- Describe the general structure of a neuron and identify its important anatomical regions.
Cell body - center of the neuron, has all the usual organelles except centrioles
processes - armlike fibers with dendrites (incoming messages) and axons (away messages), vary in length
Myelin Sheaths - waxy covering of nerve fibers that increases speed and protects it
Describe the composition of gray matter
and white matter.
Gray matter - do not have mylin sheaths, outside brain inside spine, depolarizer action potential
White matter - have mylin sheaths, oligodendrocytes, Schwann cells, myelin gives white matter it’s colour, inside brain outside spine, faster impulses that jump
What are the different types of functions of neurons?
Function:
Sensory (afferent) neurons - PNS neurons going inside the CNS. They inform us what is going on inside and outside the body.
Motor (efferent) neurons - CNS neurons carrying impulses outside toward the PNS to the muscles/glands/organs etc.
Interneurons (associations) - connect the motor and sensory neurons in neural pathways (CNS)
- Describe the electrical conditions of a resting neuron’s membrane, and explain how they are maintained.
-A resting neuron is polorized (there are fewer positive ions sitting on the inner face
of the neuron’s plasma membrane than there are on its outer face)
-The major positive ions inside the cell are potassium (K+), whereas
the major positive ions outside the cell are sodium (Na+)
-The polarized membrane is more permeable to K+(potassium) than to Na+(sodium) at rest, maintaining a more negative inside (fewer positive ions) compared to outside, as K+ ions exit the cell. This maintains the inactive, resting state of the neuron.
- Explain how a nerve impulse is generated and propagated along a neuron
The permeability of the cells membrane change
- resting membrane is polorized - more positively charged sodium is outside while positively charge potassium is on the inside
- stimulus initiates local depolarization - strong stimulus goes onto a patch of the membrane and sodium goes into the cell making the inside more positive then outside
- depolorization and generation of an action potential- the membrane turns positive causing the action potential moves along the fibre
- propagation of the action potential - move along the membrane like dominoes
- repolariztion - potassium ions leave the cell as membrane permeability changes again restoring the more negative charge on the inside and positive on the outside
- initial ionic conditions restored
What happens when an action potential reaches an axon terminal? (5)
- Calcium comes in
- neurotransmitter is released into the synaptic cleft
- Neurotransmitter cross the synaptic cleft
- a new action potential is made in the receiving neuron (depolarization)
- Neurotransmitter is quickly removed from the cleft
What are the 4 major regions of the brain?
Cerebral Hemispheres - thinking and sensing
Diencephalon - relay information (thalamus) and control body functions: temperature, hunger, thirst, sleep, etc.
Cerebellum - balance and posture
Brain stem - keeps you alive - breathing, heart rate, etc. Connects brain to spinal cord
- Identify the three meninges and describe their functions.
meninges - connective tissue membranes covering and protecting the CNS structures (brain and spinal cord)
- Dura Matar - durable outter layer
- Arachnoid mater - middle cobweb layer
3.Pia mater - soft inner layer
What is cerebrospinal fluid?
a watery broth cushion protecting the brain and spinal cord.
It helps it float against the pressure of its own weight
Constantly moving
- Describe the structure and function of the blood-brain barrier.
A semi permeable membrane with tight junctions protecting the brain from harmful substances.
Only water, glucose, and essential amino acids pass through to the brain.
Astrocytes help strengthen the barrier.
What is the spinal cord and spinal nerves.
spinal cord - nerve highway connects brain to body. Extends from foramen magnum to L1 or L2
Spinal nerves - Connected to the spinal cord with 31 pairs of dorsal and ventral roots
Which neuroglia are most abundant in the body?
Astrocytes
Which neuroglia produce the insulating material called myelin?
Oligodendrocytes in the central nervous system
Schwann cells in the peripheral nervous system
Why is a brain tumour more likely to form in neuroglia than neurons?
Neurons do not divide, neuroglia do
What is the parasympathetic and sympathetic division from the autonomic nervous system?
Parasympathetic - rest and digest (brain and sacral spinal region)
Sympathetic- fight or flight (thoracic and lumbar spinal region)
Where is the CNS located and where is the PNS located?
CNS - brain and spinal cord
PNS - outter body
The nervous system is known as the master _________ and ________ system of the body
Control and communication
The nervous system communicates with body cells using ____________
Electrical impulses
The sensory and motor fibers are part of the ___________ nervous system
Peripheral nervous system
Glial cells or glia is another name for _________ cells
Neuroglia
Which neuroglia form myelin sheaths in the CNS and the PNS?
CNS - oligodendrocytes
PNS - Schwann cells
