2025 Anatomy Test 4

Question 1

Nervous system characteristics

Answer 1

Controls and adjusts the activity of the body
Provides swift but brief responses

Question 2

An Overview of the Nervous System

Answer 2

The nervous system consists of all the nervous tissue and includes:

Central Nervous System (CNS)
Associated with the brain and the spinal cord

Peripheral Nervous System (PNS)
Associated with the tissue outside the CNS

Question 3

Central nervous system (CNS)

Answer 3

Responsible for integrating, processing, and coordinating sensory input

Responsible for integrating, processing, and coordinating motor output

It is the seat of intelligence, memory, learning, and emotion

Question 4

Peripheral nervous system (PNS)

Answer 4

Provides sensory information to the CNS and carries motor commands away from the CNS

Can be divided into:
Afferent division
Brings sensory information to the CNS
Begins at the receptors

Efferent division
Carries motor commands to muscles and glands
Ends at the effectors

Question 5

The peripheral nervous system (PNS) can be subdivided into:

Answer 5

Afferent
Can be further subdivided into somatic and visceral
Somatic - sensory from skin, skeletal muscles and joint
Visceral - internal organs, blood vessels and glands

Efferent
Can be further subdivided into somatic nervous system (SNS) and autonomic nervous system (ANS)
The autonomic nervous system can be further divided into: (Internal Viscera)
Parasympathetic division
Sympathetic division

Question 6

Functional Overview of Nervous System

Answer 6

Question 7

Nervous tissue consists of two cell types:

Answer 7

Neurons
Nerve cells that are responsible for the transfer and processing of information in the nervous system
Consist of a soma (cell body), axon, dendrites, perikaryon, dendritic spines, and axon terminals

Neuroglia (culmination of all other cells)
Supporting cells
Protect the neuron
** 5 Types

Question 8

Types of Neuroglia of the CNS

Answer 8

Astrocytes: largest and most numerous/make up the blood brain barrier (BBB)

Oligodendrocytes: form myelin sheath/form internodes and myelin sheath gaps:
Areas with mostly myelinated axons are called white matter
Areas devoid of myelinated axons are called gray matter
Gray matter is also composed of cell bodies and dendrites

Microglia: these are phagocytic cells

Ependymal Cells: involved in cerebrospinal fluid (CSF) production
Make up a cellular lining called the ependyma

Peripheral Nervous System…
… has Schwan Cells as well = help make the myelin sheath of PNS

Question 9

Histology of Nervous Tissue in CNS

Answer 9

Question 10

Types of Neuroglia of the PNS

Answer 10

The cell bodies in the PNS are clustered in ganglia

Axons are bundled together to form peripheral nerves

There are two neuroglia types:
Satellite Cells: surround cell bodies
Schwann Cells: surround axons
Schwann cells are also called neurolemmocytes
Consists of:
Axolemma/neurolemma

Question 11

Myelination

Answer 11

Nodes = Nodes of Ranvier

Question 12

Neuron structure

Answer 12

Neurons consist of:
Perikaryon: neuron cytoplasm
Neurofilaments/Neurotubules: make up the neuron cytoskeleton
Neurofibrils: bundles of neurofilaments
Nissl bodies: clusters of free ribosomes
Axon hillock: area where the initial segment connects to the cell body
Axoplasm: cytoplasm of the axon
Collaterals: branches off the axon
Telodendria: ends of the axon and collaterals
Axon terminals: ends of the telodendrias
Axoplasmic transport: the movement of material between the cell body and the axons

Question 13

Neuron Classification: Structural Classification of Neurons

Answer 13

Anaxonic
Has many processes but cannot differentiate between axons and dendrites
Found only in the CNS

Bipolar
The cell body is between the dendrite and axon
Axons are not myelinated

Question 14

Structural Classification

Answer 14

Question 15

Functional Classification of Neurons: Sensory (afferent division) Neurons

Answer 15

The axons are afferent fibers

Sends information from the PNS to the CNS

There are:
Somatic sensory neurons and visceral sensory neurons

There are three categories of receptors:
Interoceptors: monitor internal organ activity
Exteroceptors: provide information about the external environment
Proprioceptors: monitor position and movement

Question 16

Functional Classification of Neurons: Motor Neurons

Answer 16

The axons are efferent fibers

Send information from the CNS to the periphery

Consist of two divisions:
Somatic nervous system (SNS): consists of somatic motor neurons
Autonomic nervous system (ANS): consists of visceral motor neurons
Also consists of: preganglionic fibers and postganglionic fibers

Question 17

Functional Classification of Neurons: Interneurons

Answer 17

Located entirely in the CNS

Situated between the motor and sensory neurons

Analyze sensory input and coordinate motor outputs

Can be excitatory or inhibitory

Question 18

Synaptic Communication

Answer 18

Nerves connect to other nerves
Nerves connect effector organ

A synapse is the junction between a neuron and another cell

Two major types of synapses:
Chemical synapse (vesicular)
Electrical synapse (nonvesicular)

Question 19

Neuron Organization and Processing

Answer 19

Neurons can be organized into smaller organized groups called neuronal pools

The neuronal pools are identified by their neural circuit such as:
Divergence
Convergence
Serial processing
Parallel processing
Reverberation

Question 20

Neuron Organization and Processing: Serial and Parallel

Answer 20

Question 21

Neuron Organization and Processing: Reverberation

Answer 21

Question 22

Anatomical Organization of the Nervous System

Answer 22

Neurons in the PNS
Consist of ganglia
Axons are bundled together in nerves

Neurons in the CNS
Collection of cell bodies called a center
If this center has a distinct boundary, it is called a nucleus
White matter consists of axons in bundles called tracts and columns

Question 23

Autonomic nervous system (ANS)

Answer 23

The autonomic nervous system (ANS) functions outside of our conscious awareness

The autonomic nervous system makesroutine adjustments in our body’s systems

The autonomic nervous system:
Regulates body temperature
Coordinates cardiovascular, respiratory, digestive, excretory, and reproductive functions

Question 24

A Comparison of the Somatic and Autonomic Nervous Systems

Answer 24

Autonomic nervous system
Has afferent and efferent neurons
Efferent axons innervate the visceral organs
Preganglionic axons synapse on postganglionic neurons at a ganglion
A ganglion is a group of neurons outside of the central nervous system

Autonomic nervous system
Afferent pathways originate at visceral sensory receptors

Somatic nervous system
Has afferent and efferent neurons
Efferent axons innervate the skeletal muscles
Somatic motor neurons do not involve ganglia

Somatic nervous system
Afferent pathways originate in the skeletal muscles, joints, and skin.

Question 25

A Comparison of the Somatic and Autonomic Nervous Systems

Answer 25

Sympathetic and Parasympathetic Subdivisions of the ANS The autonomic nervous system consists of two major subdivisions Sympathetic division Also called the thoracolumbar division Most active during times of stress, exertion, or emergency Parasympathetic division Also called the craniosacral division (preganglionic axons leave the spinal cord at the cranial and sacral division of spinal cord) Most active during resting conditions

Question 26

ANS - Sympathetic Division

Answer 26

Dorsal and ventral horns??? But between T1 and L5 there is an addition of a lateral horn which is Grey Matter/cell bodies Grey matter vs White matter??? Pre-ganglionic = short axons Post-ganglionic nerve = long axons Most in a row close to spinal cord = sympathetic ganglionic chain

Question 27

ANS - Parasympathetic System

Answer 27

Live in the cranial and sacral section Pre-ganglionic = long axons Post-ganglionic nerve = short axons

Question 28

ANS: ENS... the third system

Answer 28

The autonomic nervous system consists of a third division: Enteric nervous system (ENS) Neurons located in the walls of the digestive tract Many visceral reflexes are initiated by the ENS, but receive input from the ANS

Question 29

The Sympathetic Division

Answer 29

Sympathetic division consists of: Preganglionic neurons between T1 and L2 Neuronal cell bodies in ganglia (ganglionic neurons) near the vertebral column Sympathetic chain ganglia Collateral ganglia Specialized neurons in the interior of the adrenal gland

Question 30

The Sympathetic Division Specifics

Answer 30

Sympathetic Chain Ganglia Also called paravertebral ganglia or lateral ganglia Located on both sides of the vertebral column Postganglionic efferents control effectors in the body wall, head, neck, limbs, and thoracic cavity Collateral Ganglia Also called prevertebral ganglia Neurons innervate effectors in the abdominopelvic cavity Adrenal Medulla Modified sympathetic ganglion—releases neurotransmitters into bloodstream

Question 31

The Sympathetic Chain Ganglia

Answer 31

Preganglionic neurons short and myelinated only exit CNS via ventral roots of T1 to L2 Travel to ganglion via spinal nerve and white ramus communicans Synapse with postganglionic neurons in chain ganglia Postganglionic neurons Long and unmyelinated Exit chain ganglia via gray ramus communicans Innervate glands and smooth muscle in the body wall and blood vessels, and viscera in the head and thorax. Ventral Ramus??? Posterior Ramus??? Two rami communicans??? YOUTUBE this!!!!

Question 32

Ganglionic Chain can go up or down...

Answer 32

Question 33

Distribution of Sympathetic Post Ganglionic Fibers

Answer 33

A Summary of the Sympathetic Division Consists of parallel chains on either side of the spinal cord Preganglionic fibers are short, myelinated, and extend from the spinal cord to the sympathetic chain Postganglionic fibers are long, unmyelinated, and extend to the effector organs

Question 34

The Parasympathetic Division

Answer 34

Preganglionic neurons are in the brainstem and sacral segments (craniosacral) Preganglionic neurons do not diverge as much as the sympathetic division Therefore, the parasympathetic division is more localized and specific as compared to the sympathetic division Synapses with postganglionic neurons occur either near the target organ (terminal) or within the target organ (intramural)