Nervous and Endocrine Systems Quiz

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Questions and Answers

What is a primary characteristic of the nervous system compared to the endocrine system?

Uses neurotransmitters (correct)

Targets multiple organs

Responses are slower

Actions last longer

Which function is NOT typically associated with the nervous system?

Integrates sensory information

Monitors environmental changes

Secretes hormones for systemic effects (correct)

Coordinates voluntary responses

How do the durations of responses in the nervous system and endocrine system primarily differ?

Nervous system responses are shorter in duration (correct)

Both systems have short-lived responses

Endocrine system responses are immediate

Nervous system responses last longer

What is one way that the endocrine system is different from the nervous system?

It uses hormones that affect multiple targets Signup and view all the answers

Which of the following statements best describes the speed of the nervous system's response?

It is immediate and rapid Signup and view all the answers

Which cells produce an insulating membranous wrapping around axons in the central nervous system?

Oligodendrocytes Signup and view all the answers

What condition is characterized by the demyelination of peripheral nerves due to an autoimmune response?

Guillain-Barré Syndrome Signup and view all the answers

What role do satellite cells play in the peripheral nervous system?

Surround and support neuron cell bodies Signup and view all the answers

Which of the following describes the effect of altered microglial function in relation to Alzheimer’s disease?

They have strong associations with neurodegenerative processes Signup and view all the answers

What is demyelination?

Damage to the protective myelin sheath surrounding neurons Signup and view all the answers

Which type of neuron is most common in the central nervous system and has multiple dendrites?

Multipolar neuron Signup and view all the answers

Where is the cell body located in a unipolar neuron?

Off to one side Signup and view all the answers

What is the primary function of sensory neurons?

Receive information from sensory receptors Signup and view all the answers

Which type of neuron typically has one dendrite and one axon with the cell body in the middle?

Bipolar neuron Signup and view all the answers

Interneurons primarily function by:

Receiving information in the CNS and transmitting it to motor neurons Signup and view all the answers

What is the primary function of Na+ K+ pumps in a cell?

Ejects 3 Na+ out of the cell and brings in 2 K+ Signup and view all the answers

Which condition describes the resting membrane potential in neurons?

-70 mV Signup and view all the answers

What happens to the membrane when it is depolarized?

The membrane potential becomes less negative Signup and view all the answers

What is the primary difference between potassium and sodium ion passage through the membrane?

Potassium ions pass through more readily than sodium ions Signup and view all the answers

Which of the following ions is typically found in higher concentrations in the extracellular fluid (ECF)?

Sodium (Na+) Signup and view all the answers

What is the primary function of dendrites in a neuron?

Receiving signals from other neurons or sensory receptors Signup and view all the answers

What occurs during the repolarization phase of an action potential?

Potassium ions leave the neuron Signup and view all the answers

Which part of the central nervous system primarily processes information related to emotions and memory?

Cerebrum Signup and view all the answers

What is the role of neurotransmitters in synaptic transmission?

To bind to receptors on target cells and transmit signals Signup and view all the answers

Which statement best explains the significance of the myelin sheath?

It increases the speed of signal transmission along the axon Signup and view all the answers

What consequence does the refractory period have on action potential propagation?

It prevents the generation of new action potentials temporarily Signup and view all the answers

Which structure contains the synaptic vesicles that release neurotransmitters?

Axon terminal Signup and view all the answers

What is the role of nodes of Ranvier in neuronal function?

They enable saltatory conduction to occur along myelinated axons Signup and view all the answers

Study Notes

Neurophysiology Overview

This course, Neurophysiology, is for HBS1.2 students in October 2024.
Students will learn about the anatomical and functional divisions of the nervous system, neuron structure and types, neuroglia functions, action potential generation/propagation, and synapse structure/mechanism.

Lesson Objectives

Describe the anatomical and functional divisions of the nervous system.
Describe the structure of a neuron.
Recall the structural and functional types of neurons.
Recall the functions of neuroglia.
Understand the events involved in the generation and propagation of an action potential.
Describe the structure and mechanism of a synapse.

Integration and Coordination

The nervous system and endocrine system work together to maintain homeostasis.
The nervous system responds faster with short-term action, using neurotransmitters and targeting specific cells.
The endocrine system responds slower, with longer-acting actions using hormones that act on multiple targets.

Functions of the Nervous System

Monitors the body's internal and external environments.
Integrates sensory information.
Coordinates voluntary and involuntary responses.

Anatomical Divisions of the Nervous System

Central Nervous System (CNS): Consists primarily of the brain and spinal cord. It integrates and coordinates input and output.
Peripheral Nervous System (PNS): All neural tissues outside the CNS, connecting the CNS to other organs.

Functional Overview of the Nervous System

Central Nervous System (CNS): Includes brain and spinal cord.
Peripheral Nervous System (PNS): Composed of Sensory nerves (afferent) bringing information to CNS, and Motor nerves (efferent) transmitting information from CNS.
- Somatic sensory - from skin, muscles, joints, and special senses
- Visceral sensory - from body organs
- Somatic motor - to skeletal muscles (voluntary)
- Autonomic motor - to smooth muscles, cardiac muscles, and glands (involuntary) - further subdivided into sympathetic ("fight or flight") and parasympathetic ("rest and digest") divisions.

Structure of the Neuron

Nervous tissue is made of two main types of cells:
- Neurons: The basic unit, transmitting nerve impulses.
- Neuroglia: Supporting cells, protecting and regulating the environment around neurons.
Neuron structure:
- Cell body with nucleus and organelles.
- Dendrites that receive signals.
- Axon hillock where electrical signals begin.
- Axons that carry signals to other cells.
- Synaptic terminals where the axon forms a synapse to another cell.
Neurons have a limited ability to regenerate if damaged.

Myelinated Neuron Anatomy

Myelin sheath: A lipid covering on long axons, increasing conduction speed and providing insulation.
Nodes of Ranvier: Gaps in the myelin sheath, crucial for saltatory conduction.
Myelin is mostly present in PNS.

Structural Classification of Neurons

Multipolar: Most common neuron type in CNS and efferent neurons
Unipolar: Most sensory neurons. Two or more dendrites, one axon. Cell body is located off to one side.
Bipolar: Found in special sensory organs. One dendrite and one axon with the cell body in the middle.

Functional Classification of Neurons

Sensory (afferent) neurons: Receive information from sensory receptors.
Interneurons: Receive information in the CNS and transmit it to motor neurons.
Motor (efferent) neurons: Carry information to peripheral targets called effectors.

Neuroglia Functions

Supportive cells that make up about half of neural tissue. Able to divide and regenerate.
- Astrocytes: Nutritional support for neurons, maintaining blood-brain barrier, and associated with Alzheimer's Disease.
- Ependymal cells: Related to cerebrospinal fluid (CSF) production and circulation.
- Oligodendrocytes: Myelinate CNS axons; provide structural framework.
- Microglia: Defensive cells removing cell debris and pathogens.
- Satellite cells: Surround neuron cell bodies, regulating levels of O2, CO2, nutrients, and neurotransmitters.
- Schwann cells: Surround axons in PNS, involved in myelination and peripheral axon repair.

Neuroglia - Clinical Notes

Demyelination: Damage to the myelin sheath impacting nerve impulse conduction – associated with multiple sclerosis, and Guillain-Barré Syndrome.
Chronic exposure to certain heavy metals (arsenic, lead, mercury) negatively affects neuroglia.

Neurophysiology: Action Potential

Action potential (nerve impulse): An all-or-none electrical signal propagating along a neuron.
The events are categorized as depolarization, repolarization, and reestablishment of the resting potential.
Resting potential: -70mV, maintained by ion pumps and channels.
Depolarization and repolarization are governed by ion channels and pumps.
Graded potentials: Local changes in membrane potential.
Action potential: A change in membrane potential that travels the entire length of a neuron.

Propagation of Action Potential:

Continuous propagation: Occurs in unmyelinated axons, relatively slow.
Saltatory propagation: Occurs in myelinated axons, significantly faster.

Neurophysiology: Synapse

A synapse is a functional junction between a neuron and another cell (target).
Communication occurs unidirectionally.
Neurotransmitters: Chemical messengers released from the presynaptic neuron to the post synaptic cell at the synapse. Target cells are neurons, muscles, or glands.
Neurotransmitters of synapses bind to receptors.
Cholinergic synapses: Synapses that release Acetylcholine (ACh). Found in neuromuscular junctions, many CNS synapses, and all PNS synapses.

Important Neurotransmitters

Excitatory neurotransmitters: Facilitate information transmission to the postsynaptic cell (e.g., acetylcholine, glutamate, dopamine, norepinephrine).
Inhibitory neurotransmitters: Inhibit information transmission to the postsynaptic cell (e.g., GABA, glycine).

Clinical Notes on Synapses

Botulism: A toxin that prevents the release of acetylcholine from motor neurons, leading to paralysis and preventing muscle contraction.
Myasthenia gravis: An autoimmune disease affecting neuromuscular junctions, interfering with acetylcholine leading to muscle weakness.
Neuromuscular blocking drugs: Bind to ACh receptors, preventing synaptic transmission, leading to muscle paralysis.
- Examples include some local anesthetic drugs

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Description

Test your knowledge of the nervous and endocrine systems with this comprehensive quiz. Explore key differences, functions, and characteristics of these vital biological systems. From neuron types to response durations, challenge yourself and deepen your understanding of human physiology.