Nervous System Overview and Classification

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Questions and Answers

What is the primary function of the cerebrospinal fluid (CSF)?

To generate neurotransmitters for communication

To increase the weight of the brain within the skull

To act as a shock absorber and prevent brain injury (correct)

To transport nutrients to nerve cells

In the brain, where is the white matter located compared to the gray matter?

Inner part of the brain (correct)

Distributed evenly throughout the brain

Only in the brainstem

Outer part of the brain

Which structure surrounds the brain and spinal cord, providing protection?

Meninges (correct)

Cerebrospinal fluid (CSF)

Neuroglia

White matter

What characterizes the arrangement of gray and white matter in the spinal cord?

White matter is on the outer part and gray matter is on the inner part Signup and view all the answers

What is the significance of the blood-brain barrier?

It limits access of blood-borne materials into the brain Signup and view all the answers

What type of neuron carries sensory impulses from the periphery to the central nervous system?

Afferent neurons Signup and view all the answers

Which type of synapse involves the axon of a presynaptic neuron ending on the soma of a postsynaptic neuron?

Axosomatic synapse Signup and view all the answers

What is the primary function of motor neurons?

Carrying motor impulses to effector organs Signup and view all the answers

Which classification of synapse allows for direct ionic exchange between neurons?

Electrical synapse Signup and view all the answers

Which component is NOT part of the anatomical classification of synapses?

Chemical synapse Signup and view all the answers

What is the primary site of formation for cerebrospinal fluid (CSF)?

Choroid plexuses Signup and view all the answers

Which of the following substances can pass through the blood-brain barrier (BBB)?

Amino acids Signup and view all the answers

What is a significant difference between cerebrospinal fluid (CSF) and blood?

CSF is lower in potassium and higher in sodium than blood. Signup and view all the answers

What role does the blood-brain barrier (BBB) serve in the brain?

Prevents harmful substances and permits essential materials into brain tissues. Signup and view all the answers

Which of the following statements about the blood-brain barrier (BBB) is true?

The BBB protects brain tissues from pathogens and harmful substances. Signup and view all the answers

Study Notes

Nervous System Overview

The nervous system is comprised of neurons and neuroglia
Structures of the brain and spinal cord are arranged in two layers
Gray matter is composed of nerve cell bodies and proximal parts of nerve fibers arising from nerve cell bodies.
White matter is composed of the remaining parts of nerve fibers

Nervous System Classification

Anatomical classification: based on the structures of the brain, spinal cord, and peripheral nerves
Functional classification: based on the function of the system, somatic and autonomic systems.

Nervous System Components

Central Nervous System (CNS): includes the brain and spinal cord
- Brain: is subdivided into the cerebral cortex, cerebellum, brain stem and others
- Spinal cord: extends from the foramen magnum to the vertebral column
Peripheral Nervous System (PNS): consists of cranial nerves and spinal nerves, divided into
- Somatic nervous system
- Autonomic nervous system: includes sympathetic and parasympathetic nervous systems

Synapse

Synapse is the junction between two neurons
It is not an anatomical continuation, only a physiological continuity
Anatomical classification methods include:
- Axoaxonic synapse: axon of presynaptic neuron ends on axon of postsynaptic neuron
- Axodendritic synapse: axon of presynaptic neuron connects with dendrite of postsynaptic neuron
- Axosomatic synapse: axon of presynaptic neuron ends on the soma (cell body) of postsynaptic neuron
Functional classification
- Electrical synapse: the physiological continuity between both neurons is provided by gap junctions.
- Chemical synapse: neurotransmitter is released from one neuron, crosses the synaptic cleft. and triggers a response in the postsynaptic neuron.

Protection and Nourishment of the Brain

Central nervous tissue is delicate
Encased by hard, bony structures (cranium and vertebral column)
Protected by meninges (three layers):
- Dura mater
- Arachnoid mater
- Pia mater
Surrounded by cerebrospinal fluid (CSF) a cushioning fluid
Blood-brain barrier (BBB) selective limits substances entering the brain from the blood stream

Cerebrospinal Fluid (CSF)

CSF surrounds the brain and spinal cord
Acts as a shock absorber against mechanical injury
Facilitates the exchange of materials between neural cells and interstitial fluid
CSF differs in composition from blood

Blood-Brain Barrier (BBB)

Neuroprotective structure that prevents entry of many substances and pathogens into the brain tissues from blood
Exists in capillary membrane of all parts of the brain, except some areas of hypothalamus.

Functions of the Blood-Brain Barrier (BBB)

Acts as a mechanical barrier and transport mechanisms
Prevents potentially harmful chemical substances from entering the brain tissue
Permits entry of essential materials
BBB provides a healthy environment for nerve cells

Reflex Activity

Reflex activity is the nervous systems response to stimulation that occurs without consciousness.
Reflex arc is the anatomical nervous pathway for a reflex action, consisting of: Stimulus, Receptor, Afferent Nerve, Center, Efferent Nerve, Effector Organ

CNS Functional Levels

Three major levels with specific functional characteristics:
- Spinal cord level: responsible for walking movements, reflexes, and control of local blood vessels
- Lower brain or subcortical level: responsible for control of subconscious activities, such as arterial pressure, respiration, equilibrium cerebellum
- Higher brain or cortical level, including the cerebral cortex, responsible converting the functions of lower brain centers into definitive operations including memory, intelligence, and higher functions

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Description

Explore the intricate structures and classifications of the nervous system, including its central and peripheral components. This quiz covers the key aspects of neurons, neuroglia, gray and white matter, and the functional divisions of the nervous system.