Nervous System Overview

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Questions and Answers

What are the two main types of brain matter?

Grey matter and white matter (correct)

Grey matter and black matter

Grey matter and pink matter

Grey matter and yellow matter

Which structure connects the two hemispheres of the brain?

Coronal fissure

Corpus callosum (correct)

Cerebral sinus

Corpus calcaneum

Where is cerebrospinal fluid (CSF) produced?

In the basal ganglia

At the corpus callosum

Choroid plexus in the lateral ventricle (correct)

In the white matter

What is the function of neuroglia?

To support and protect neurons Signup and view all the answers

Which of these structures is NOT a ventricle of the brain?

Spinal canal Signup and view all the answers

What lines the ventricles of the brain?

Ependyma Signup and view all the answers

Which type of matter is found primarily on the cortex of the brain?

Grey matter Signup and view all the answers

Which of the following best describes the CSF flow direction?

From third ventricle to fourth ventricle Signup and view all the answers

Which type of neuron has a cell body with one neurite that divides shortly after the cell body?

Unipolar neurons Signup and view all the answers

What is the primary function of neurons?

To transmit information to other nerve cells, muscle, or gland cells Signup and view all the answers

Which of the following structures conducts impulses away from the cell body?

Axons Signup and view all the answers

Which of these is NOT a type of neuron based on structure?

Tripolar neurons Signup and view all the answers

What do dendrites do in a neuron?

Receive information and conduct it towards the cell body Signup and view all the answers

In which part of the body are multipolar neurons primarily found?

Brain and spinal cord Signup and view all the answers

Which components make up the basic working unit of the brain?

Neurons Signup and view all the answers

What role do auxiliary cells play in the nervous system?

Support and protect neurons Signup and view all the answers

Where is cerebrospinal fluid (CSF) primarily produced?

Lateral ventricles Signup and view all the answers

What structure does CSF flow through to reach the third ventricle?

Interventricular foramen Signup and view all the answers

After flowing through the cerebral aqueduct, where does CSF go next?

Fourth ventricle Signup and view all the answers

Which structures allow CSF to course through the subarachnoid space?

Lateral and median apertures Signup and view all the answers

How is CSF reabsorbed into the venous circulation?

Through the arachnoid granulations Signup and view all the answers

Which layer of the meninges is closest to the brain?

Pia mater Signup and view all the answers

Which of the following best describes the function of cerebrospinal fluid (CSF)?

Protects the brain from physical impact Signup and view all the answers

What is the relationship between the skull and the meninges?

The skull is covered by the meninges. Signup and view all the answers

Which two vertebral levels are recommended for performing a spinal tap?

L3/L4 and L4/L5 Signup and view all the answers

What is the primary function of the cranial nerve III (oculomotor)?

Eye movements Signup and view all the answers

What type of tissue is found directly beneath the dura mater before reaching the subarachnoid space?

Areolar tissue with internal vertebral venous plexus Signup and view all the answers

How many pairs of spinal nerves are there in the human body?

31 Signup and view all the answers

Which of the following cranial nerves is responsible for hearing and balance?

CN VIII Signup and view all the answers

Which division of the peripheral nervous system is responsible for the 'fight or flight' response?

Sympathetic Signup and view all the answers

Which lumbar nerve is primarily responsible for sensations in the lower legs?

L5 Signup and view all the answers

What type of fibers do spinal nerves contain?

A mixture of sensory and motor fibers Signup and view all the answers

Which nervous system is primarily associated with the 'fight or flight' response?

Sympathetic nervous system Signup and view all the answers

What is the primary function of the parasympathetic nervous system?

Promote relaxation and digestion Signup and view all the answers

Where do sympathetic fibers originate in the spinal cord?

Thoracolumbar region Signup and view all the answers

Which of the following is a characteristic of the sympathetic nervous system response?

Increases heart rate Signup and view all the answers

What is the primary effect of the parasympathetic system on the heart?

Decrease heart rate Signup and view all the answers

Which cranial nerves are involved in the parasympathetic nervous system?

CN III, CN VII, CN IX, CN X Signup and view all the answers

What is a key difference between the sympathetic and parasympathetic nervous systems?

Location of pre-synaptic cell bodies Signup and view all the answers

Which of the following describes the action of the sympathetic system on blood vessels during stress?

Dilates blood vessels to muscles Signup and view all the answers

Study Notes

Introduction

The nervous system is responsible for receiving, processing and responding to stimuli in the body.
The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).

Nervous System Cells

Nerve cells (Neurons) are the functional unit of the nervous system.
- Neurons are specialized cells that are excitable and responsible for transmitting information.
- They vary in size and shape.
- They are present throughout the brain, spinal cord, and ganglia.
Neuroglia are supportive cells that provide nutrition, protection, and structural support to neurons.

Neuron Structure

Cell body: Contains the nucleus and other organelles.
Dendrites: Receive information from other neurons and conduct it towards the cell body.
Axons: Conduct impulses away from the cell body, transmitting information to other neurons, muscles, or glands.

Neuron Types

Unipolar neurons: Have a single neurite that divides a short distance from the cell body. Found in dorsal root ganglia.
Bipolar neurons: Have an elongated cell body with an axon and dendrite at each end. Found in sensory ganglia.
Multipolar neurons: Have numerous processes arising from the cell body. Found in brain and spinal cord.

Central Nervous System (CNS)

Cerebrum: The largest part of the brain, responsible for higher-level functions such as thought, language, and memory.
Corpus callosum: A band of nerve fibers that connects the two hemispheres of the cerebrum.
Grey matter: Consists of nerve cell bodies and neuroglia. Found in the cortex and scattered throughout the core (basal ganglia).
White matter: Consists of nerve fibers and neuroglia. Located centrally/inner matter.

Ventricles

Cerebrospinal fluid (CSF): A clear, colorless fluid that fills the ventricles and the subarachnoid space surrounding the brain and spinal cord.
- Produced at a rate of 500ml/day by the choroid plexus within the ventricles.
- Provides cushioning and protection for the CNS.
Ventricles: CSF-filled cavities within the brain.
- Two lateral ventricles
- One third ventricle
- One fourth ventricle

Meninges

Meninges: Three layers of protective membranes that surround the brain and spinal cord.
- Dura mater: The outermost, tough, fibrous layer.
- Arachnoid mater: Middle layer, delicate and web-like.
- Pia mater: Innermost layer, closely attached to the brain and spinal cord.

Spinal Tab

The spinal tab is a procedure used to collect CSF.
It is performed at L3/L4 or L4/L5, where the spinal cord has ended.

Peripheral Nervous System (PNS)

Nerve: A collection of many axons.
Cranial nerves: 12 pairs of nerves that arise from the brain.
- Olfactory nerve (CN I): Smell.
- Optic nerve (CN II): Vision.
- Oculomotor nerve (CN III), Trochlear nerve (CN IV) and Abducent nerve (CN VI): Eye movements.
- Trigeminal nerve (CN V): Facial and scalp sensation, mandibular movements.
- Facial nerve (CN VII): Facial expression.
- Vestibulocochlear nerve (CN VIII): Hearing and balance.
- Glossopharyngeal nerve (CN IX) and Vagus nerve (CN X): Swallowing and phonation.
- Accessory nerve (CN XI): Neck and head movements.
- Hypoglossal nerve (CN XII): Tongue movements.
Spinal nerves: 31 pairs of nerves that arise from the spinal cord.
- 8 cervical nerves (neck and upper limbs)
- 12 thoracic nerves (upper limbs and thorax)
- 5 lumbar nerves (abdomen and lower limbs)
- 5 sacral nerves (lower limbs and perineum)
- 1 coccygeal nerve

Autonomic Nervous System (ANS)

Visceral motor system: Controls the involuntary functions of the body (smooth muscle, cardiac muscle, and glands). Composed of two branches:
- Sympathetic nervous system (SNS): 'Fight or flight' response.
  - Increases heart rate and contractility, dilates blood vessels to muscles, dilates pupils, dilates bronchioles, closes sphincters.
  - Derived from cells in the lateral horn (T1-L2) of the spinal cord.
- Parasympathetic nervous system (PSNS): 'Rest and digest' response.
  - Decreases heart rate and contractility, constricts pupils, constricts bronchioles, opens sphincters.
  - Derived from cranial nerves (CNIII, CNVII, CNIX, CNX) and sacral nerves (S2-4).

Autonomic Nervous System Organization

Preganglionic neuron: Neuron whose cell body is in the CNS and whose axon makes a synapse with a postganglionic neuron in a ganglion.
Postganglionic neuron: Neuron whose cell body is in the ganglion and whose axon reaches the target organ.
Sympathetic ganglia: Clusters of postganglionic neurons located close to the spinal cord.
Parasympathetic ganglia: Clusters of postganglionic neurons located near or within target organs.

Distinction Between Sympathetic and Parasympathetic

Location of pre-synaptic cell bodies:
- Sympathetic: Thoracolumbar region of the spinal cord.
- Parasympathetic: Cranial nerves and sacral spinal cord.
Location of post-synaptic cell bodies:
- Sympathetic: Sympathetic ganglia close to the spinal cord.
- Parasympathetic: Parasympathetic ganglia near or within target organs.

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Description

This quiz covers essential concepts about the nervous system, including its structure, the roles of neurons and neuroglia, and neuron types. Test your knowledge on how the central and peripheral nervous systems function together to process stimuli and transmit information.