Chapter 3.1 - 3.7 Anatomy of the Nervous System Flashcards
-List and describe the major divisions of the brain. -Describe the three meninges and explain their functional role. -Explain where cerebrospinal fluid is produced and where it flows. -Explain what the blood-brain barrier is and what functional role it serves. -Draw, label and define the major features of a multipolar neuron. -Describe 4 kinds of glial cells. -Compare several neuroanatomical research techniques. -illustrate the neuroanatomical directions -draw and label cross section of spinal c
What are the two divisions of the vertebrate nervous system?
The central nervous system and the peripheral nervous system
What is the central nervous system (CNS)?
Division of nervous system located within the skull and spine
-brain and spinal cord
What is the peripheral nervous system (pns)?
The division of the nervous system located outside the brain and spine
The peripheral nervous system is composed of two divisions what are they?
The somatic nervous system (SNS)
and
the autonomic nervous system (ANS)
What is the somatic nervous system (SNS)
Part of the Peripheral Nervous System (PNS) that interacts with with the external environment.
What is the Autonomic Nervous System (ANS)?
Part of the Peripheral Nervous System (PNS) that regulates the body’s internal environment.
What are the two nerve types that make up the Somatic Nervous System (SNS)?
Afferent Nerves
Efferent Nerves
In the SNS, what is the purpose of Afferent Nerves?
Carry sensory signals from the skin, skeletal muscles, joints, eyes, ears, etc. to the CNS
Afferent = TO CNS (advance, approach, arrive)
In the SNS what is the purpose of Efferent Nerves?
Carry motor signals from the CNS to the skeletal muscles
Efferent = FROM CNS (exit, embark, escape)
In the ANS, there are two nerve types, what are they?
- Efferent Nerves
2. Afferent Nerves
In the ANS, what do the Afferent Nerves do?
Carry Sensory signals from the internal organs to the CNS
Afferent = approach CNS
In the ANS, what do the Efferent Nerves do?
Carry motor signals from the CNS to Internal Organs
Efferent = Exiting CNS
The Autonomic Nervous System has two kinds of efferent nerves, what are they?
- Sympathetic nerves
2. Parasympathetic Nerves
In the autonomic nervous system, what do the sympathetic nerves do?
Autonomic motor nerves
-project from CNS in the LUMBAR (small of back) and THORACIC (chest) regions of the spinal cord
In the ANS what do the Parasympathetic Nerves do?
autonomic motor nerves
-project from the brain and SACRAL (lower-back) region of the spinal cord
what does it mean that all sympathetic and parasympathetic nerves are “Two-Stage Neural Paths”?
The sympathetic and parasympathetic neurons project from the CNS and go only part of the way to the target organs before they SYNAPSE on other (second-stag) neurons
What are the 3 important principles stressed about the functions of the sympathetic and parasympathetic systems?
- Sympathetic nerves stimulate, organize and mobilize energy resources in Threatening Situations (parasympathetic act to conserve energy)
- Each autonomic target organ receives opposing sympathetic and parasympathetic input (activity controlled by relative levels of each systems input)
- Sympathetic changes indicate psychological arousal (parasympathetic changes indicate psychological relaxation)
Most of the nerves of the PNS project from the spinal cord. There are 12 Pairs of exceptions. What are the and where do they project from?
Cranial Nerves
Project from the brain
What are the three protective membranes that cover the brain and spinal cord?
3 Meninges:
1. Dura Mater meninx (membrane) - tough, outermost layer
2. Arachnoid meninx (membrane) - spiderweb like, middle membrane
Separating 2 and 3: Subarachnoid space - contains many large blood vessels and cerebrospinal fluid
3. Pia Mater meninx (membrane) - innermost, adheres to surface of CNS
What is the purpose of cerebrospinal fluid and where is it located?
Supports and cushions the brain.
- fills subarachnoid space
- fills central canal of spinal cord
- fills cerebral ventricles of the brain
What is the central canal?
Small central channel that runs the length of the spinal cord
What are the cerebral ventricles?
4 Large internal chambers of the brain
2 lateral ventricles
3rd ventricle
4th ventricle
What produces cerebrospinal fluid?
Choroid plexuses:
-networks of capillaries that protrude into the ventricles from the Pia Mater Meninx
What happens to excess cerebrospinal fluid?
continuously absorbed from the subarachnoid space into large blood-filled spaces (Dural Sinuses)
-Dural sinuses run through the Dura Mater and drain into the large jugular veins of the neck
What is the purpose of the blood-brain barrier?
Prevents the passage of many toxic substances from the blood to the brain
-cells of the blood vessels of the brain are tightly packed = forms a barrier
what are neurons?
Cells that are specialized for the reception, conduction and transmission of electrochemical signals
What is a multipolar neuron?
Neuron with more than 2 processes extending from its cell body
What is a unipolar neuron?
Neuron with 1 process extending from is cell body
What is a bipolar neuron?
neuron with 2 processes extending from cell body
What is an interneuron? what is their function?
Neuron with short axon (or no axon)
-integrate neural activity within a single brain structure (rather than conduct signals between structures)
There are two kinds of gross neural structures in the nervous system, what are they?
- Those composed mostly of cell bodies
2. Those composed mostly of axons
In the central Nervous System, what are clusters of cell bodies called?
Nuclei
In the Peripheral Nervous system, what are clusters of cell bodies called?
Ganglia
In the central nervous system, what are bundles of axons called?
Tracts
In the peripheral nervous system, bundles of axons are called?
Nerves
What are oligodendrocytes?
Glial cells with extensions(rich in myelin = forms myelin sheath) that wrap and the axons of some neurons of the CNS
-increases speed and efficiency of axonal conduction
What are Schwann Cells?
In PNS.
Similar to Oligodendrocytes in that the have myelin sheaths, but differ as, unlike oligodendrocytes, each Schwann cell constitutes only one myelin segment
-another difference is Schwann cells can guide axonal regeneration
-increases speed and efficiency of axonal conduction
What are microglia?
- Smallest glial cell
- respond to injury or disease by multiplying, engulfing cellular debris and triggering inflammatory responses
What are astrocytes?
Largest glial cells - star-shaped
- extensions of some cover outer surfaces o blood vessels that course through the brain (may play a role in allowing some chemicals from blood into CNS)
- make contact wit neurons
- can contract and relax blood vessels based on flow demands of particular brain regions
