Introduction to Nervous and Endocrine Systems

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Questions and Answers

What is the main function of the endocrine system?

Controlling rapid movements

Producing electrical nerve impulses

Releasing hormones into the blood (correct)

Interpreting sensory information

Which system interprets sensory information and issues instructions in the body?

Central Nervous System (CNS) (correct)

Muscular system

Endocrine system

Digestive system

What is the approximate weight of the adult human brain?

42-45 centimeters

1,300-1,400 grams (correct)

2 centimeters

35 grams

What is the approximate weight of the spinal cord?

35 grams Signup and view all the answers

Which system controls with rapid electrical nerve impulses?

Nervous system Signup and view all the answers

What is the role of the brain in the nervous system?

Acting as the integrating center of the CNS Signup and view all the answers

How does the endocrine system bring about its effects?

By releasing hormones into the blood Signup and view all the answers

What is not a part of the Central Nervous System?

Endocrine system Signup and view all the answers

Which type of neurons carry impulses from the sensory receptors to the central nervous system?

Sensory neurons Signup and view all the answers

Where are the cell bodies of interneurons located?

In the central nervous system Signup and view all the answers

Which type of neurons have a single process leaving the cell body?

Unipolar neurons Signup and view all the answers

What is the main function of motor neurons?

Carry impulses from the central nervous system to muscles and glands Signup and view all the answers

Which neurons connect sensory and motor neurons?

Interneurons Signup and view all the answers

What is the term for the ability of a neuron to respond to stimuli and convert them into nerve impulses?

Irritability Signup and view all the answers

Which type of neurons have many processes extending from the cell body?

Multipolar neurons Signup and view all the answers

What distinguishes unipolar neurons in terms of dendrites?

Only the small branches at the end of the peripheral process are dendrites Signup and view all the answers

What is the function of dendrites in a neuron?

Conduct messages toward the cell body Signup and view all the answers

Where are most neuron cell bodies found?

In the central nervous system Signup and view all the answers

What is the main function of axons in a neuron?

Conduct impulses away from the cell body Signup and view all the answers

What kind of nerves carry impulses to and from the brain?

Cranial nerves Signup and view all the answers

What are Schwann cells responsible for in nerve fibers?

Producing myelin sheaths Signup and view all the answers

Which division of the peripheral nervous system carries information from sensory receptors to the central nervous system?

Sensory division Signup and view all the answers

Which part of a neuron contains the nucleus and metabolic center of the cell?

Cell body Signup and view all the answers

What is the function of supporting cells (neuroglia/glial cells) in nervous tissue?

Support, insulate, and protect neurons Signup and view all the answers

What is the function of Neurofibrils in a neuron?

Maintain cell shape Signup and view all the answers

Which part of the peripheral nervous system is responsible for voluntary activities like skeletal muscle movement?

Somatic nervous system Signup and view all the answers

What are Nodes of Ranvier along an axon's myelin sheath?

Gaps or indentations Signup and view all the answers

What does the term 'synapse' refer to in the context of neurons?

"Junction between nerves" Signup and view all the answers

What is the role of motor (efferent) division in the peripheral nervous system?

Carry impulses away from the central nervous system Signup and view all the answers

Which type of nerve fibers bring about responses in effector organs, muscles, and glands?

Motor nerve fibers Signup and view all the answers

Which subdivision of the autonomic nervous system controls involuntary activities like smooth muscle function?

Autonomic nervous system Signup and view all the answers

What is the main function of cranial nerves in the peripheral nervous system?

Carry impulses to and from the brain Signup and view all the answers

What is the term used to describe the ability to transmit an impulse to other neurons, muscles, or glands?

Conductivity Signup and view all the answers

During depolarization of a neuron's membrane, what ions flow inside the membrane?

Sodium (Na+) Signup and view all the answers

What happens to the membrane during repolarization?

Sodium ions rush out Signup and view all the answers

What cellular process restores the original configuration of ions in a neuron post-action potential?

Active transport Signup and view all the answers

In which direction does the nerve impulse move after it is propagated over the entire axon?

Toward the cell body Signup and view all the answers

What greatly speeds up impulse transmission when fibers have it?

Myelin sheath Signup and view all the answers

What is released from a nerve's axon terminal to facilitate communication between neurons at synapses?

Neurotransmitter Signup and view all the answers

Which part of the next neuron is stimulated by the neurotransmitter released at a synapse?

Receptors on dendrite Signup and view all the answers

What initiates an action potential in the dendrite of the next neuron during communication at synapses?

$Na^+$ ions rush in Signup and view all the answers

What is responsible for restoring the original configuration of ions in a neuron after action potential?

Sodium-Potassium pump Signup and view all the answers

Study Notes

The Nervous System

The nervous system consists of two parts: the central nervous system (CNS) and the peripheral nervous system (PNS)
The PNS includes nerves outside the brain and spinal cord, which serve as communication lines that link all parts of the body

Functional Classification of the PNS

Two subdivisions: sensory (afferent) division and motor (efferent) division
Sensory division: carries information from sensory receptors to the CNS
Motor division: carries impulses away from the CNS to effector organs, muscles, and glands

Motor Division Subdivisions

Somatic nervous system: voluntary, controls skeletal muscles (reflexes)
Autonomic nervous system: involuntary, controls smooth and cardiac muscles and glands

Nervous Tissue Structure and Function

Supporting cells (neuroglia/glial cells): provide support, insulation, and protection for delicate neurons
The endocrine system works with the nervous system to regulate and maintain body homeostasis

Organization of the Nervous System

CNS: brain and spinal cord, acts as the integrating and command center
PNS: nerves outside the brain and spinal cord
Ganglia: small collections of cell bodies outside the CNS
Tracts: bundles of nerve fibers running through the CNS
Nerves: bundles of nerve fibers running through the PNS

Functional Classification of Neurons

Sensory (afferent) neurons: carry impulses from sensory receptors to the CNS
Motor (efferent) neurons: carry impulses from the CNS to muscles and glands
Interneurons (association neurons): connect sensory and motor neurons in the CNS

Structural Classification of Neurons

Multipolar neurons: many processes extending from the cell body
Bipolar neurons: two processes, one axon and one dendrite
Unipolar neurons: a short single process leaving the cell body

Neuron Anatomy

Cell body: contains the nucleus and metabolic center of the cell
Processes: fibers that extend from the cell body
Dendrites: conduct impulses toward the cell body
Axons: conduct impulses away from the cell body
Axonal terminals: contain vesicles with neurotransmitters

Axons and Nerve Impulses

Axonal terminals release neurotransmitters into the synaptic cleft
Synapse: junction between nerves
Myelin sheaths: produced by Schwann cells, insulate and facilitate nerve impulse transmission

Nerve Fiber Coverings

Schwann cells: produce myelin sheaths around nerve fibers
Nodes of Ranvier: gaps in myelin sheath at regular intervals along the axon

Neuron Cell Body Location

Most cell bodies are found in the CNS
Nuclei: clusters of cell bodies within the white matter of the CNS
White matter: contains dense collections of myelinated fibers (tracts)
Gray matter: contains unmyelinated fibers and cell bodies

Neuron Function

Conductivity: ability to transmit an impulse to other neurons, muscles, or glands
Irritability: ability to respond to stimuli and convert it into a nerve impulse

Nerve Impulse Propagation

Depolarization: a stimulus depolarizes the neuron's membrane
Action potential: the exchange of ions initiates an action potential in the neuron
Repolarization: potassium ions rush out of the neuron after sodium ions rush in
Sodium-potassium pump: restores the original configuration, requires ATP

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Description

Explore the coordination and regulation of body functions by the nervous and endocrine systems. Learn about the structural classification of the nervous system and the production of hormones by endocrine system organs. Dive into the unique mechanisms through which these systems maintain homeostasis.