Biology Chapter 11: Nervous System

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Questions and Answers

What are the three essential roles of the nervous system?

Sensing, Communicating, Moving

Sensing, Analyzing, Responding

Sensing, Integrating, Responding (correct)

Sensing, Deciding, Reacting

Which component is part of the Central Nervous System?

Hormones

Spinal cord (correct)

Sensory receptors

Nerves in the arms

How does the nervous system primarily communicate signals?

Using electrical signals (correct)

Through blood circulation

By chemical messengers called hormones

Via muscle contractions

Which organ system works alongside the nervous system to coordinate bodily functions?

Endocrine system Signup and view all the answers

Which cells are considered the building blocks of the nervous system?

Neurons Signup and view all the answers

What is the primary function of neuroglia in the nervous system?

Protect and support neurons Signup and view all the answers

Which cells form myelin sheaths in the peripheral nervous system?

Schwann cells Signup and view all the answers

What is the primary role of the blood-brain barrier?

To protect the brain from foreign substances Signup and view all the answers

Which statement accurately describes sensory neurons?

They detect external stimuli and send signals to the CNS. Signup and view all the answers

What type of tumor is a glioma?

Highly malignant and rapidly growing Signup and view all the answers

What is the primary function of the myelin sheath?

To insulate the axon and speed up impulse conduction Signup and view all the answers

What occurs at the nodes of Ranvier?

Action potentials are generated Signup and view all the answers

What part of the neuron is primarily responsible for receiving signals from other neurons?

Dendrites Signup and view all the answers

What is the consequence of the myelin sheath deteriorating in multiple sclerosis?

Formation of scar tissue called plaques Signup and view all the answers

Which statement accurately describes unmyelinated nerve fibers?

They conduct nerve impulses more slowly. Signup and view all the answers

What is one of the common symptoms associated with neurological conditions?

Visual disturbances Signup and view all the answers

What causes vesicles to fuse with the plasma membrane during synaptic transmission?

Calcium ion entry Signup and view all the answers

What is the role of a neurotransmitter in synaptic transmission?

To determine if the impulse continues or stops Signup and view all the answers

Which process occurs after the neurotransmitter binds to receptors on the postsynaptic membrane?

Reuptake by the postsynaptic neuron Signup and view all the answers

What is one of the initial steps that happens when an action potential reaches a synaptic knob?

Membrane depolarization Signup and view all the answers

Study Notes

Homeostasis and Nervous System Overview

Homeostasis is the balance maintained by organ systems working cooperatively.
The nervous system comprises the brain, spinal cord, and nerves, continuously receiving internal and external signals.
Two major systems coordinate cellular activities: the endocrine system (hormones) and the nervous system (electrical signals).

Essential Roles of the Nervous System

Sensing: Uses sense organs and nerve endings to detect internal and external changes.
Integrating: Processes information, correlates with past experiences, and decides appropriate responses.
Responding: Sends commands to muscles and glands to elicit changes based on processed information.

Divisions of the Nervous System

Central Nervous System (CNS): Encompasses the brain and spinal cord.
Peripheral Nervous System (PNS): Comprises a vast network of nerves throughout the body.

Nervous System Cells

Two main types of cells are present: Neurons (communicate signals) and Neuroglia (support and protect neurons).

Neuroglia

Also known as glial cells, meaning "glue," serve as supportive cells in the nervous system.

Cell Types

CNS Neuroglia:
- Oligodendrocytes form myelin sheaths, enhancing signal conduction.
PNS Neuroglia:
- Schwann cells create myelin sheaths around peripheral nerves, forming the neurilemma.

Blood-Brain Barrier (BBB)

Formed by astrocytes and endothelial cells, it acts as a semi-permeable membrane.
Allows small molecules to pass but blocks larger ones, protecting the brain from foreign substances.
Complicates treatment for brain disorders due to limited access for medications.

Neurons

Nerve cells responsible for communication within the nervous system.

Classes of Neurons

Sensory Neurons (Afferent): Detect stimuli (touch, pressure, heat, chemical changes) and relay information to the CNS.

Neuron Structure

Comprises three main parts:
- Cell Body (Soma): Central control, contains the nucleus.
- Dendrites: Receive signals and conduct information to the soma.
- Axon: Transmits nerve signals away from the soma; typically has only one axon.
Myelin Sheath: Lipid-rich insulation around axons, facilitating rapid impulse conduction.
Nodes of Ranvier: Gaps in the myelin sheath that enhance signal transmission.
Synaptic Knob: Branches at the axon terminal where neurotransmitter release occurs.
Myelination begins in the fetal stage and is not complete until late adolescence.

Life Lesson: Multiple Sclerosis

MS involves deterioration of myelin sheaths in the CNS, replaced by scar tissue (plaques).

Common Symptoms of MS

Visual disturbances (blindness/double vision).
Weakness and loss of coordination.
Speech difficulties.

Synaptic Transmission Process

Action potential triggers synaptic activity.
Membrane depolarization allows calcium ions to enter.
Calcium facilitates vesicle fusion and neurotransmitter release into the synapse.
Neurotransmitter binds to receptors on the postsynaptic membrane, influencing continuation (excitation) or cessation (inhibition) of the impulse.
Released neurotransmitters are reabsorbed by synaptic knobs after receptor binding.

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Description

Explore the fascinating functions of the nervous system in this quiz. Understand how it works in conjunction with the endocrine system to maintain homeostasis in the body. Test your knowledge on the structure and communications of these vital organ systems.