Nervous System Quiz (BMS Learning Outcomes)

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Questions and Answers

Which cell type in the central nervous system is primarily responsible for forming and maintaining myelin?

Schwann cells

Microglia

Astrocytes

Oligodendrocytes (correct)

What is the primary role of cerebrospinal fluid (CSF) regarding the brain?

Acts as a storage medium for neurotransmitters

Serves as a cushioning buffer (correct)

Facilitates nerve impulse transmission

Carries nutrients directly to the neurons

Which part of the central nervous system is considered the control center for autonomic functions like hunger and thirst?

Medulla oblongata

Cerebellum

Hypothalamus (correct)

Thalamus

Which statement best describes the function of microglia in the nervous system?

Act as the primary immune defense in the CNS Signup and view all the answers

Which of the following is NOT a feature of the central nervous system?

Sensory neurons Signup and view all the answers

What is the consequence of excessive nerve impulses, particularly related to trigeminal neuralgia?

Increased pain sensitivity Signup and view all the answers

What aspect of the medulla oblongata is crucial for survival?

Control of reflex centers Signup and view all the answers

In the context of local anesthetics, which ion channel is primarily affected to inhibit nerve transmission?

Sodium channel Signup and view all the answers

Which part of the nervous system is characterized by voluntary control over muscle movement?

Somatic nervous system Signup and view all the answers

What is one function of the thalamus related to sensory information?

Processes auditory and visual information Signup and view all the answers

What is the primary function of dendrites in a neurone?

Receive information and pass it to the cell body Signup and view all the answers

Which of the following statements about neurones is true?

They consist of a cell body, an axon, and several dendrites. Signup and view all the answers

What is the role of Schwann cells in the peripheral nervous system?

Provide myelin insulation to axons Signup and view all the answers

What type of cells support the neurones in the central nervous system?

Neuroglial (glial) cells Signup and view all the answers

How do nodes of Ranvier contribute to nerve impulse transmission?

They assist in the rapid transmission of action potentials. Signup and view all the answers

What describes the myelin sheath surrounding large axons in the peripheral nervous system?

It is formed by layers of Schwann cells. Signup and view all the answers

Which property of neurones allows them to initiate nerve impulses?

Irritability Signup and view all the answers

Which of the following structures is primarily involved in neurotransmitter storage?

Synaptic end bulb Signup and view all the answers

Where are cell bodies of nerve cells predominantly located in the nervous system?

In the grey matter of the brain and central spinal cord Signup and view all the answers

Study Notes

Nervous Tissue Characteristics and Cells

Neurons: The nervous system's fundamental units. Each neuron has a cell body, one axon, and many dendrites. Bundles of axons are called nerves.
Irritability: Neurons can generate nerve impulses in response to internal or external stimuli.
Conductivity: Neurons transmit electrical impulses.
Cell Body: Forms grey matter, located in the brain periphery and spinal cord center. Contains a nucleus and organelles, but lacks mitosis, so cannot be replaced (although regeneration is possible).
Axon: Carries impulses away from the cell body, can be very long (over 1 meter). Larger axons in the peripheral nervous system are myelinated.
Schwann Cells: Wrap around axons, creating the myelin sheath, primarily in the peripheral nervous system. Myelin is a fatty substance that electrically insulates the axon.
Nodes of Ranvier: Gaps in the myelin sheath between Schwann cells. They facilitate fast impulse transmission.
Dendrites: Extensions of the cell body with a large surface area for receiving signals. Similar structure to axons but shorter. Dense with ion channels for impulse transmission. Link to other dendrites or sensory receptors.
Synaptic End Bulb: Site of communication between neurons or between a neuron and an effector (muscle or gland). Contains synaptic vesicles storing neurotransmitters (e.g., acetylcholine, noradrenaline).

Supporting Cells (Glial Cells)

Neuroglia: Non-excitable cells that support and protect neurons in the central nervous system. They continually replicate.
- Microglia: Primary function is phagocytosis (engulfing debris) in areas of inflammation or cell damage. Commonly found near blood vessels.
- Astrocytes: Star-shaped cells forming the main supporting tissue of the CNS. Found near blood vessels and in a muccopolysaccharide matrix.
- Oligodendrocytes: Smaller than astrocytes and create myelin in the central nervous system. Analogous to Schwann cells in the periphery.

Nerve Impulse Mechanisms

Local Anesthetics: Block nerve impulses by inhibiting sodium channels in nerve cell membranes. Used in dentistry to manage pain during procedures.
Neuralgia: Excessive nerve impulses can cause neuralgia, like trigeminal neuralgia.
Herpes Simplex Virus: The virus can lie dormant in the trigeminal ganglion, reactivate, and cause cold sores along the trigeminal nerve.

Divisions of the Nervous System

Central Nervous System (CNS): Brain and spinal cord.
Peripheral Nervous System (PNS): All other nerves.
- Sensory Division: Carries sensory information to the CNS.
- Motor Division: Carries signals from the CNS to effectors.
  - Somatic: Voluntary movement of skeletal muscles.
  - Autonomic: Involuntary control of smooth muscle, cardiac muscle, and glands.

Key Brain Structures

Cerebrum: Largest part; responsible for higher mental activities, sensory perception, and voluntary muscle control.
Hypothalamus: Located in the cerebrum; controls hormones, emotional reactions, hunger/thirst, body temp, and biological clocks.
Thalamus: Relays sensory information (touch, pain, temperature) from sensory receptors to the brain for initial perception. Involved in arousal and emotions.
Midbrain: Consists of nuclei that relay information between the cerebrum and spinal cord. Involved in auditory and visual reflexes.
Pons: Forms a bridge between the cerebrum's hemispheres and processes information from cranial nerves.
Medulla Oblongata: Continuous with spinal cord; controls vital functions like the cardiovascular and respiratory centers, and reflex centers (e.g., coughing, vomiting).

Spinal Cord

Structure: Long, cylindrical part of the CNS, extends from the medulla oblongata, suspended in the vertebral canal, surrounded by meninges and cerebrospinal fluid.
Function: Conveys impulses from the brain to organs and tissues.

Cerebrospinal Fluid (CSF) Functions

Protection: Cushions the brain and reduces the pressure at the base.
Buoyancy: Reduces the brain's net weight.
Waste Removal: Transports waste from the brain to the bloodstream.
Endocrine Medium: Carries hormones to various brain areas.

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Description

Explore the fundamental components and functions of nervous tissue, including neurons, irritability, and conductivity. Learn about the structure and roles of key cellular elements like the axon and Schwann cells. This quiz provides insights into how these cells contribute to the nervous system's functionality.