Choroid Plexus and Cerebral Hemispheres

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Questions and Answers

What is the structural feature that separates the cervical enlargement from the rest of the spinal cord?

Posterior median septum

Arachnoid layer

Dorsal root ganglion

Conus terminalis (correct)

Which layer of the spinal meninges is described as the innermost and highly vascular?

Pia mater (correct)

Arachnoid

Periosteum

Dura mater

What fluid is found in the subarachnoid space?

Cerebrospinal fluid (correct)

Lymphatic fluid

Synovial fluid

Interstitial fluid

What are the two types of paralysis mentioned in relation to spinal injuries?

Quadriplegic and Paraplegic Signup and view all the answers

Which of the following spaces is located between the dura mater and the arachnoid layer?

Subdural space Signup and view all the answers

What is the composition of the white matter in the spinal cord?

Myelinated fiber tracts Signup and view all the answers

Where is cerebrospinal fluid primarily produced?

Choroid plexus of the brain Signup and view all the answers

What is true about the dorsal root ganglion?

It houses the fibers entering the spinal cord. Signup and view all the answers

What is the primary function of oligodendrocytes?

Produce myelin sheath Signup and view all the answers

What characteristic does not describe neuroglia?

Transmit nerve impulses Signup and view all the answers

What is the term for the conduction of nerve impulses in myelinated fibers?

Saltatory conduction Signup and view all the answers

Which cell type in the peripheral nervous system forms myelin sheaths around nerve fibers?

Schwann cells Signup and view all the answers

What is the primary function of mixed nerves?

Carry both sensory and motor fibers Signup and view all the answers

Which structure carries out reflex actions without immediate involvement of the brain?

Reflex arc Signup and view all the answers

Which part of the autonomic nervous system is responsible for mobilizing the body during extreme situations?

Sympathetic part Signup and view all the answers

Which factor is known to impair the conduction of nerve impulses?

Alcohol consumption Signup and view all the answers

What binds all fascicles together to form a cordlike nerve?

Epineurium Signup and view all the answers

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

12 pairs Signup and view all the answers

What type of reflex involves skeletal muscles?

Somatic reflex Signup and view all the answers

How many pairs of spinal nerves are part of the spinal cord?

31 pairs Signup and view all the answers

What type of motor neuron is found in the ganglion of the autonomic nervous system?

Postganglionic neuron Signup and view all the answers

Which spinal nerves form the intercostal nerves?

T1 through T12 Signup and view all the answers

What is the purpose of the perineurium in nerve structure?

Bind fiber bundles into fascicles Signup and view all the answers

Which of the following does not describe a function of the autonomic nervous system?

Handles conscious skeletal muscle movement Signup and view all the answers

What is the primary function of the choroid plexus?

To form cerebrospinal fluid Signup and view all the answers

Which part of the brain is responsible for the conscious movement of skeletal muscles?

Primary Motor Area Signup and view all the answers

What distinguishes a sulcus from a fissure in the cerebral cortex?

A sulcus surrounds a gyrus, whereas a fissure divides the brain into lobes Signup and view all the answers

Which structure in the midbrain is primarily involved in auditory and visual reflexes?

Corpora Quadrigemina Signup and view all the answers

Where is Broca's area located, and what is its function?

In the frontal lobe; speech production Signup and view all the answers

What is one of the main functions of the pons in the brain stem?

Participating in the control of breathing Signup and view all the answers

Which of the following structures connects the third ventricle to the fourth ventricle?

Cerebral Aqueduct Signup and view all the answers

Which of the following best describes the function of the medulla oblongata?

It regulates vital visceral functions Signup and view all the answers

What is another name for the sympathetic division?

Thoracolumbar Division Signup and view all the answers

Where are the preganglionic neurons of the parasympathetic division primarily located?

Brain nuclei of cranial nerves and S2 and S4 spinal cord levels Signup and view all the answers

What neurotransmitters are released by the postganglionic fibers of the sympathetic division?

Norepinephrine and Noradrenalin Signup and view all the answers

Which division of the autonomic nervous system is primarily active during rest?

Parasympathetic Division Signup and view all the answers

What type of fibers do the sympathetic postganglionic fibers release?

Adrenergic fibers Signup and view all the answers

What anatomical feature allows preganglionic axons to enter the sympathetic chain ganglia?

White ramus communicans Signup and view all the answers

Which term describes the sympathetic division's function during perceived threats?

Fight or flight Signup and view all the answers

In which region do pelvic splanchnic nerves primarily function?

Pelvic cavity Signup and view all the answers

Study Notes

Neuroglia

Glial cells do not transmit nerve impulses but aid in neuronal function.
Neuroglia retain the ability to divide throughout life; most brain tumors stem from these cells (gliomas).
Supporting cells in the Central Nervous System (CNS) include:
- Astrocytes: Anchor neurons to blood capillaries, providing structural support.
- Microglia: Act as scavengers that remove debris such as dead cells and bacteria.
- Ependymal Cells: Circulate cerebrospinal fluid (CSF) and form a protective cushion around the CNS.
- Oligodendrocytes: Produce the myelin sheath that insulates neuronal axons.
Supporting cells in the Peripheral Nervous System (PNS):
- Schwann Cells: Generate myelin sheaths around nerve fibers.
- Satellite Cells: Provide protection and cushioning for neuronal cell bodies.

Physiology of Nerve Impulses

Neurons exhibit two primary functional properties:
- Irritability: Ability to respond to stimuli and convert them into nerve impulses.
- Conductivity: Capability to transmit impulses to neurons, muscles, or glands.
Saltatory Conduction: Fast transmission in myelinated fibers where impulses jump between nodes of Ranvier due to insulation from myelin.
Impairments of Conduction: Influenced by alcohol, sedatives, anesthetics, cold temperatures, and sustained pressure.

Reflex Arc

Reflex: An involuntary response to stimuli.
- Somatic Reflex: Involves skeletal muscles.
- Visceral Reflex: Involves smooth muscle, cardiac muscle, or glands.
- Spinal Reflex: Conducted by spinal cord neurons without immediate brain involvement.

Anatomy of the Spinal Cord

Comprises 31 pairs of spinal nerves, bridging the brain and most body parts.
Functions:
- Connects the brain with the body.
- Facilitates spinal reflex actions (both somatic and visceral).
It extends from the foramen magnum to the first lumbar vertebra, approximately 47 cm long.
Contains significant anatomical features, including:
- Cervical and Lumbosacral enlargements: Indicate regions of increased neural processing.
Meninges: Three protective layers surrounding the spinal cord:
- Dura Mater: Tough outer layer.
- Arachnoid: Middle layer that extends to S2 vertebra.
- Pia Mater: Innermost vascular layer.
Spaces:
- Epidural Space: Contains blood vessels and fat.
- Subdural Space: Minimal space between dura and arachnoid, no cerebrospinal fluid (CSF).
- Subarachnoid Space: Contains CSF and blood vessels.

Cerebrospinal Fluid (CSF)

A clear, watery fluid derived from blood, produced primarily in the choroid plexus of the brain.
Provides cushioning and nutrient supply for the brain and spinal cord.

Internal Structure of the Spinal Cord

Central Canal: Contains CSF.
Gray Matter: Dark, H-shaped region including dorsal and ventral horns.
White Matter: Composed of myelinated fiber tracts, categorized into:
- Posterior Column: Carries sensory input to the brain.
- Anterior and Lateral Columns: Responsible for motor output.

The Cerebral Hemispheres

Gyri: Elevated ridges of tissue.
Sulci: Shallow grooves between gyri; larger grooves are termed fissures.
Critical areas:
- Somatic Sensory Area: Located in the parietal lobe, processes touch, pain, and temperature sensations.
- Primary Motor Area: Located in the frontal lobe, responsible for voluntary movement.
- Broca's Area: Associated with speech production.

Structures of the Brainstem

Midbrain: Controls motor movement and processes auditory and visual information; consists of:
- Cerebral Aqueduct: Connects third and fourth ventricles.
- Cerebral Peduncles: Transmit impulses.
- Corpora Quadrigemina: Involved in reflex actions for vision and hearing.
Pons: Contains nuclei essential for breathing regulation and neurological pathways.
Medulla Oblongata: Regulates vital autonomic functions and contains many neural tracts.

Nerves

Mixed Nerves: Carry both sensory and motor fibers.
Afferent Nerves: Sensory nerves transmitting signals to the CNS.
Efferent Nerves: Motor nerves transmitting information from the CNS.

Autonomic Nervous System (ANS)

A subdivision of the PNS that automates bodily functions: heart rate, digestion, and respiratory rate.
Comprises two motor neurons:
- Preganglionic Neuron: Located in the CNS.
- Postganglionic Neuron: Resides in ganglia outside the CNS.
Has two divisions:
- Sympathetic Division: Mobilizes the body during stress ("fight or flight").
- Parasympathetic Division: Promotes relaxation and energy conservation ("rest and digest").

Functionality of ANS

Organs receive input from both divisions and produce antagonistic effects.
Neurotransmitters:
- Parasympathetic fibers release acetylcholine (cholinergic fibers).
- Sympathetic fibers release norepinephrine (adrenergic fibers).

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Description

Explore the key functions of the choroid plexus, including its role in forming cerebrospinal fluid, and examine the structure of the cerebral hemispheres, highlighting gyri and sulci. This quiz will enhance your understanding of the protective mechanisms of the brain and its anatomical features.