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
A nerve cell may have hundreds of _________ but only one _____________
However, at its end there are hundreds of _________
Hundreds of branching dendrites but only one axon
Axon terminals
What are the nodes of ranvier
The gaps in between the Schwann cells forming a myelin sheath
What are bundles of nerve fibers (processes) called running through the CNS and PNS?
CNS - tracts
PNS - nerves
Think of nerves running along the train tracts (bundle of nerve fibres)
Ganglion and nuclius are cell body’s
What are interneurons (association neurons)?
Where sensory neuron’s and motor neuron’s meet in the spinal cord or brain (CNS)
How does a ganglion differ from a nucleus?
Ganglion - cell bodies in PNS
Nuclei- cell bodies in CNS
Which part of a neuron conducts impulses toward the cell body in multipolar and bipolar neurons?
Which part releases neurotransmitters?
Dendrites conduct electrical impulses toward the cell body
Axon terminal release’s neurotransmitters
The __________ produce cerebrospinal fluid
Choroid plexuses
The corpus callosum connects the __________
Right and left cerebral hemispheres
What is the difference between the sympathetic nervous system and the parasympathetic nervous system?
Sympathetic- fight or flight response increases heart rate, dilate oxygen tract and pupils, etc.
Parasympathetic - rest, dominates under normal circumstances
The cell bodies of sensory neurons whose fibers enter the spinal cord are found in the ____________
Dorsal root ganglion
Together with the brain stem, the ___________ oversees all subconscious, autonomic functions
Diencephalon
What is the thalamus?
Major relay station for ascending sensory information
___________ reflexes regulate skeletal muscle
A: autonomic or somatic
Somatic
Damage to which cranial nerves may impair the sense of taste?
Facial and glossopharyngeal
What are tracts and nuclei and where are they located
What are ganglia and nerves and where are they located?
Tracts - CNS bundles of nerve fibres
Nuclei - CNS clusters of neuron cell bodies
Nerves - PNS bundles of nerve fibres
Ganglia - PNS clusters of neuron cell bodies
The cerebellum aids in maintenance of _____________
Balance and posture
The three connective tissue membranes covering and protecting CNS structures are collectively known as the ____________. The ____________ is the outermost leathery layer.
Meninges, dura mater
The deep groove that separates the two hemispheres of the cerebrum is called the _____________
Longitudinal fissure
All motor and association neurons are _____________
Multipolar
What is a reflex ? What is a somatic reflex and an autonomic reflex?
Reflex - a preprogrammed response to a stimulus
Reflexes don’t need higher thinking
They can be somatic (pulling your hand away from a hot object) - fast action muscles
or autonomic (making saliva or dilating pupils) - internal organs moving automatically (don’t have to think about it)
What are the 5 elements of a reflex arc?
3 neuron reflex arc?
2 neuron reflex arc?
- Receptor
- Sensory neuron (afferent)
- Integration centre (interneuron cell)
- Motor neuron (efferent pathway)
- Effector organ
Sensory (afferent) neuron > interneuron > motor (efferent) neuron
Sensory (afferent) neuron > motor (efferent) neuron
Reflexes don’t need higher thinking
What is the difference between a graded potential and an action potential?
Graded potential - small, vary in size, fades as it spreads
Action potential - big, all or nothing, continuously regenerated along the length of an axon and does not die out
Graded potentials are like a flicker of light, while action potentials are like a full on switch being turned on
What is Saltatory conduction?
Jumping down the nerves myelin sheaths at the nodes of ranvier
What are the different structures of neurons? (3)
multipolar neuron - multiple processes/ dendrites extending from the cell body (most motor and association neurons are multipolar)
bipolar neurons - two processes -one axon and one dendrite extending from cell body, only special sense organs like eyes and nose have them as receptors
unipolar neurons - single process - single axon with a head sticking out the middle, sensory neurons found in PNS ganglia, one way street
True or false: electrical impulses always travel from dendrite to axon terminal
True
Where do motor impulses cross over in the brain stem from one side of body to opposite side of brain?
Medulla oblongata
What are the ridges of the brain called?
Outside bumps - gyrus
Shallow grooves - sulcus
Deepest ridge - fissure
What is the difference between your primary motor area (red) and primary somatic sensory area of the brain (blue)?
Primary Motor area (red) - muscle impulses control centre, impulses go down (like making your eye wink)
Primary somatic Sensory area (blue) - receive sensation on skin, impulses come up (like sun or breeze)
What is the deepest fissure called that separates the right and left cerebral hemispheres?
Longitudinal fissure
Which cerebral areas are involved with the 5 senses?
Sight - occipital lobe (back)
Touch - parietal (top)
Sound - temporal (side)
Smell - temporal (side)
Taste - temporal (side)
What is the Broca’s area of the brain?
What is the wernicki area in the brain?
Broca’s area - Helps you talk (talking)
Wernicki area - helps you understand speech (listening)
What is the large fibre tract called that connects the cerebral hemispheres?
Corpus callosum
What is the basal nuclei?
Islands of Gray matter in the cerebrum that helps control movement making them smooth and controlled
Example: when reaching for a cup, it makes sure your hand doesn’t shake or move in ways you don’t want it to
What is the thalamus, hypothalamus, and epithalamus?
Thalamus - relay station
Hypothalamus - regulates hunger, body temperature,
Epithalamus -emotions and sleep
What are the 4 structures of the brain stem?
Midbrain
Pons
Medulla oblongata
Reticular formation
What is reticular formation?
Filter for sensory information, filters out background noise
What are the 4 lobes of your cerebrum?
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
Which brain region controls such vital activities as breathing and blood pressure ?
The brain stem
In what major brain area is the thalamus, hypothalamus, and pineal gland found?
Diencephalon
What are the three protections of the CNS besides bone?
Meninges, cerebrospinal fluid, and blood-brain barrier
Where is cerebrospinal fluid made?
Where is it drained to the blood?
It is made in choroid plexuses in brain ventricles
It is returned to the blood in arachnoid granulations
True or false: meninges protect and extend beyond the spinal cord
True
What is the cauda equina?
What is the cervical and lumbar enlargement?
Horses tail of nerves at the end of spinal cord
The points where the nerves serving the limbs connect to the spinal cord
What is in the central canal of the the spinal cord?
Cerebrospinal fluid
Damage to the ventral nerve would mean
Flaccid paralysis - no nerve impulses would reach the muscles
In the spinal cord, All tracts in the dorsal column are _________ sensory tracts, but lateral and ventral columns have ____________ motor tracts
Ascending sensory tracts being carried to the brain
Ascending and descending motor tracts
What is found in the gray matter of the spinal cord?
The unmylinated parts of a nerve - nerve cell bodies of interneurons and motor neurons
What is important about the medulla oblongata?
It is where the left and right body-brain crossover happens
It regulates vitals - breathing, heart rate, blood pressure etc.
What is a neurilemma
The outside of a Schwann cells myelin sheath, helps regenerate nerve fibres (something that cannot be done in the CNS)
How does a tract differ from a nerve?
How does a ganglion differ from a nucleus?
Tract is a bunch of fibres in CNS, nerve is a bunch of fibres in PNS
Nucleus is cell bodies in CNS, ganglion is cell body’s in PNS
True or false: myelinated axons move faster
True
What is the anterior association area involved in?
What is the posterior association area involved in?
Anterior association area- higher intellectual reasoning, social skills
Posterior association area- patterns, faces, the big picture
In which part of the brain are vitals controlled like heart rate, breathing, swallowing, blood pressure etc?
The medulla oblongata in the brain stem
Where can the choroid plexuses be found and what do they do?
They are found in the brains ventricles making cerebrospinal fluid from blood
The protective ______________ has the least permeable capillaries to protect this sensitive organ from its environment
But it is useless against _____________
Blood brain barrier
Fats and respiratory gasses (alcohol and nicotine)
What is the name given to the cerebral spinal fluid filled cavities within the brain?
Ventricles
