Ch. 2.2 The Nervous System Consists of Central and Peripheral Divisions Flashcards
What is the somatic nervous system?
Nerves that interconnect the brain and the major muscles and sensory systems of the body.
What is the autonomic nervous system?
Nerves that primarily control the viscera (internal organs)
Label the following systems.
A. Central nervous system (CNS)
B. Peripheral nervous system
What are A, B, and C?
A. brain
B. spinal cord
C. cauda equina
What is the gross neuroanatomy?
Tissue of the nervous system made of neuronal cell bodies, dendrites, axons, and glial cells (the stuff you see with the naked eye).
What does the peripheral nervous system do?
Connects all body organs and systems to the central nervous system.
What are the 2 divisions of the peripheral nervous system?
- The somatic nervous system
- The autonomic nervous system
What does soma mean?
Body
What nerves make up the somatic nervous system?
- Cranial nerves
- Spinal nerves
How many pairs of cranial nerves does each person have?
12 - one left-sided and one right-sided nerve in each pair
What do the cranial nerves serve?
The sensory and motor systems of the head and neck
What do you know about cranial nerves?
A. 12 pairs (left and right in each pair)
B. serve the sensory and motor systems of the head and neck
C. enter and leave the brain without joining the spinal cord
D. each cranial nerve has a roman numeral number and a name.
What do the colors represent?
Pink?
Blue?
Cranial nerves
Pink - Motor nerves
Blue - Sensory nerves
How many can you remember?
How many pairs of spinal nerves are there?
31 pairs (emerging at regularly spaced intervals through openings in the backbone)
What do you know about spinal nerves?
A. 31 pairs (one left-sided and one right-sided nerve in each pair)
B. emerging at regularly spaced intervals through openings in the backbone
C. Each spinal nerve is formed by the fusion of 2 distinct branches (dorsal (S) & ventral (M) roots) attached to the spinal cord
What are the 2 branches of a spinal nerve and how are they formed
dorsal root & ventral root
What does dorsal mean?
back
What does ventral mean?
Front
What does the dorsal root consist of?
Sensory projections from the body to the spinal cord (study hint: dorsal has an S and sensory starts with an S)
What does the ventral root consist of?
Motor projections from the spinal cord to the muscles
What are the segment of the spinal cord called?
A. Cervical
B. Thoracic (trunk)
C. Lumbar (lower back)
D. Sacral (pelvic)
E. Coccyx
This is a vertebra. Label the white and gray matter.
A. Gray matter
B. White matter
What is gray matter?
The interneurons and the motor neurons that send axons to the muscles.
What is the white matter?
Myelinated axons that run up and down the spinal column.
What are meninges?
The 3 membrane layers that enclose the spinal cord and brain.
A. Pia mater
B. Arachnoid
C. Dura mater
How are the spinal nerves named?
The first letter of the spinal segment with the number of that segment.
ex: a nerve connected to the 7th cervical segment is called C7
How would you name a nerve connected to 4th lumbar segment?
L4
What is the autonomic nervous system?
The brains main system for controlling the organs of the body.
Supporting the functions of the autonomic nervous system are groups (aggregates) of neurons called?
Autonomic ganglia
Where are autonomic ganglia found?
Various places in the body outside the CNS
Label the following:
A. Preganglionic neuron
B. Postganglionic neuron
Label the following:
A. CNS (central nervous system
B. Autonomic nervous system
C. Sympathetic
D. Parasympathetic
E. Peripheral nervous system
F. Somatic nervous system
G. Sensory nervous system
H. Motor nervous
What are the 3 major divisions of the autonomic nervous system?
- Sympathetic nervous system
- Parasympathetic nervous system
- Enteric nervous system
What is the purpose of the sympathetic nervous system?
It prepares the body for action - increase blood pressure. dilate pupils, heart rate quickens etc. (fight or flight response)
Where are the preganglionic cells of the sympathetic nervous system found?
The middle part of the spinal cord - thoracic and lumbar regions
Explain the basic movement of the sympathetic nervous system.
The preganglionic cells (found in the thoracic and lumbar regions) send their axons innervating the sympathetic ganglia. Postganglionic axons exiting the sympathetic ganglia spread widely through the body, innervating all of the major organ systems.
What are the sympathetic ganglia?
2 chains of ganglia that run along each side of the spinal column (part of the sympathetic nervous system)
What is the parasympathetic nervous system?
Helps the body to relax. recuperate and prepare for future action. (rest-and-digest response)
Where do parasympathetic nerves originate?
In the brainstem and sacral spinal cord.
Are parasympathetic ganglia collected in chains alongside the spinal cord?
No
Why do the sympathetic and parasympathetic systems have different effects on individual target organs?
Because each system releases different neurotransmitters.
What is norepinephrine (or noradrenaline)?
It is a neurotransmitter used by the sympathetic system to accelerate activity.
What is acetylcholine?
It is a neurotransmitter used by the parasympathetic system to slow down activity.
What is the enteric nervous system?
A network of sensory and motor neurons that regulates the functioning of the gut. Because it regulates digestive activities, it plays a key role in maintaining fluid and nutrient balances.
What does the spinal cord do?
It funnels sensory information from the body to the brain and conveys the brain’s motor commands to the body. It also controls simple behavior such as reflexes.
Name the planes of dissection the brain.
A. Horizontal plane
B. Coronal plane
C. Sagittal plane
What does medial mean?
towards the middle
What does lateral mean?
towards the side
What does ipsilateral mean?
on the same side
What does contralateral mean
on the opposite side
What does superior mean?
above
What does inferior mean?
below
What does basal mean?
toward the bottom
What does anterior (or rostral) mean?
towards the front of the brain
What does posterior (or caudal) mean?
towards the rear of the brain
What does proximal mean?
near the trunk or center of an organism
What does distal mean?
far or toward the end of a limb
What does dorsal mean?
toward the back and/or top of the head
What does ventral mean?
toward the belly
A nerve is afferent if
it carries information into a region (hint: afferent starts with a and so does at - at the region)
A nerve is efferent if
it carries information away from a region
What type of plane is this?
Horizontal plane
Sagittal
What type of plane is this?
Coronal plane
What are the cerebral hemispheres?
The right and left halves of the forebrain
What is the cerebral cortex?
The outermost rind of the cerebral hemispheres. Consists mostly of dendrites, cell bodies and axons of neurons (gray and white matter).
Gray matter is mostly made up of?
neuronal cell bodies and dendrites (they are dark shade)
White matter is mostly made up of
axons - gets its lighter appearance from the whitish fatty myelin
What could we say the difference between gray and white matter is?
Gray matter primarily receives and processes information and white matter mostly transmits information.
What are gyri (singular gyrus)
The folding of the (cerebral) cortex creates ridges of tissue
What are sulci (singular sulcus)?
furrows that separate the ridges in the cortex
Label the parts of the cortex
B & C are sulci
A is gyrus
What are the 4 major cortical regions?
Frontal lobe, Parietal lobe, Temporal lobe, Occipital lobe
What is the purpose of all the folding of the cortex (gyri and sulci)?
To greatly increase the amount of cortex that can be crammed into the skull
Name the 4 cortical lobes
A. Frontal lobe
B. Parietal lobe
C. Temporal lobe
D. Occipital lobe
What is the Sylvian fissure?
A deep sulcus that divides the temporal lobe from the other regions of the hemisphere.
What is the central sulcus?
divides the frontal and parietal lobes
Name these
B. Sylvian fissure
A. Central sulcus
What is the precentral gyrus
Part of the frontal lobe (immediately anterior to the central sulcus) which is crucial for motor control
What did Wilder Penfield’s experiments with brain mapping reveal?
That movement-controlling neurons in the precentral gyrus are organized in an orderly map of the muscles of the other side of the body
What is the postcentral gyrus?
The strip of parietal cortex located just posterior to the central sulcus which mediates the sense of touch. It is often referred to as the primary somatosensory cortex
What do the parietal lobes do?
Receives sensory info from the body and participates in spatial cognition.
What do the occipital lobes do?
Receive and process info from the eyes
What do the temporal lobes do?
Receive and process auditory information (hearing), language, sense of smell and learning and memory.
What is the corpus callous?
The main bundle of axons the connects the two hemispheres enabling communication between the two.
What does a very young embryo CNS look like and what is it called?
It looks like a tube and is called a neural tube
Why is the part of the cortex closest to the back of the head identified as being part of the forebrain?
Because the cortex is formed from the forebrain.
In brain development, what does the neural tube divide into?
Forebrain
midbrain
hindbrain
What does the forebrain (or prosencephalon) contain?
hemispheres
thalamus
hypothalamus
What is the midbrain (or mesencephalon)?
the middle of the brain
What is the hindbrain (of rhombencephalon)?
cerebellum
pons
medulla
What does the word encephalon mean?
brain
At about 50 days after conception, the forebrain shows subdivisions. What are they?
Telencephalon
Diencephalon
The hindbrain develops into several principle structures. Name them.
Metencephalon
cerebellum
pons
medulla
What does brainstem refer to?
the region that consists of the midbrain, pons and medulla
What is the cerebellum (or little brain)?
Part of the metencephalon, it is involved in the central regulation of movement
What is the pons?
Part of the metencephalon: part of the brainstem that connects the midbrain to the medulla
Label A & B
A. Precentral gyrus
B. Postcentral gyrus
What are nuclei (singular nucleus)?
aggregations (groups) of neurons between and within the major brain areas.
What are tracts?
bundles of axon between and within the major brain areas.
What are the aggregation of neurons and the bundles of axon called in the periphery?
What are the aggregation of neurons and the bundles of axon called in the brain?
Periphery: ganglia and nerves
Brain: nuclei and tracts
How and why are 1/3 of your cranial nerves devoted to a single sense?
There are 4 cranial nerves dedicated to the eye. Probably because it is a complex organ to control.
