Human Nervous System Basics

Questions and Answers

The nervous system has billions of __________.

neurons

One function of the nervous system is controlling __________ and glands.

muscle

The Central Nervous System is responsible for interpreting incoming __________ information.

sensory

The __________ is the primary center for regulating and coordinating body activities.

brain Signup and view all the answers

The __________ carries impulses to and from the spinal cord.

spinal nerves Signup and view all the answers

Neuroglia nourishes the __________ cells in the brain and spinal cord.

nerve Signup and view all the answers

Meninges are the membranes that cover the __________.

brain Signup and view all the answers

An __________ is an agent that directly influences an activity by exciting a sensory organ.

stimulus Signup and view all the answers

Each pair of spinal nerves is connected to a segment of the cord by two pairs of attachments called ______.

roots Signup and view all the answers

The 8 cervical nerves supply the ______, neck and diaphragm.

limbs Signup and view all the answers

The 12 thoracic nerves supply the muscles of the ______ and back.

chest Signup and view all the answers

The 5 lumbar nerves supply the lower ______ and some parts of the lower limb.

abdomen Signup and view all the answers

The olfactory cranial nerve is responsible for the sense of ______.

smell Signup and view all the answers

The vagus nerve stimulates digestive organs, internal organ functions such as heart rate and respiratory ______.

rate Signup and view all the answers

The somatic sensory fibers deliver impulses from skin, skeletal muscles and ______.

joints Signup and view all the answers

The motor division of the Peripheral Nervous System carries impulses away from the ______.

CNS Signup and view all the answers

The autonomic nervous system controls the activity of smooth and ______ muscles.

cardiac Signup and view all the answers

The ______ state is characterized by calming responses and maintaining homeostasis.

parasympathetic Signup and view all the answers

The basic structural and functional unit of the brain and nervous system is called a ______.

neuron Signup and view all the answers

The brain is protected by the skull and ______.

meninges Signup and view all the answers

During embryonic development, the prosencephalon is also known as the ______.

forebrain Signup and view all the answers

Study Notes

Overview of the Nervous System

Small yet complex, comprising billions of neurons.
Weighs approximately 2 kg (3% of total body weight) and controls communication within the body.

Functions of the Nervous System (C.R.I.M.E.)

Controlling muscle and glands.
Receiving sensory input from the environment.
Integrating information for processing and response.
Maintaining homeostasis, or stable internal conditions.
Establishing and maintaining muscle activity.

Key Terms

Neuropeptide: Specialized protein messengers involved in mental functions.
Neuroglia: Cells that nourish and support neurons in the brain and spinal cord.
Meninges: Membranes covering the brain, providing protection.
Myelinated: Neurons surrounded by a myelin sheath for faster impulse transmission.
Neuron: Basic nerve cell responsible for receiving and transmitting impulses.
Nerve: Bundle of neuron fibers outside the central nervous system (CNS).
Instinct: Immediate awareness without reasoning or discovery.
Stimulus: Agent influencing activity, evoking sensory responses or muscular contractions.
Impulse: Wave of excitation transmitted by nerve fibers and muscles.

Divisions of the Nervous System

Central Nervous System (CNS): Main control center interpreting sensory information and coordinating responses.
- Brain: Primary regulatory center for body activities, processing information.
- Spinal Cord: Conducting pathway for reflex actions and information between the brain and the body.
Peripheral Nervous System (PNS): Transmits impulses to and from the CNS.
- Spinal Nerves: 31 pairs connecting to specific spinal cord segments, facilitating impulse transmission.
  - Cervical Nerves: Supply limbs, neck, and diaphragm.
  - Thoracic Nerves: Supply muscles of chest and back.
  - Lumbar Nerves: Supply lower abdomen and parts of the lower limbs.
  - Sacral Nerves: Supply reproductive organs.

Cranial Nerves (12 pairs)

Olfactory: Responsible for sense of smell.
Optic: Responsible for vision and visual acuity.
Oculomotor: Controls eyelid opening and pupil constriction.
Trochlear: Governs oblique eye movement.
Trigeminal: Related to facial sensation and mastication.
Abducens: Manages lateral eye movement.
Facial: Controls facial expressions and tear production.
Vestibulocochlear: Involved in hearing and balance.
Glossopharyngeal: Responsible for taste and swallowing.
Vagus: Stimulates internal organ functions, including the heart and digestive organs.

Functional Classifications of the PNS

Sensory Division (Afferent): Nerve fibers conveying information from sensory receptors to the CNS.
- Somatic Sensory Fibers: Deliver impulses from skin, muscles, and joints.
- Visceral Sensory Fibers: Transmit information from internal organs and blood vessels.
Motor Division (Efferent): Carries impulses away from the CNS to initiate actions.
- Somatic Nervous System: Controls voluntary movements of skeletal muscles.
- Autonomous Nervous System: Regulates involuntary actions of smooth and cardiac muscles.
  - Parasympathetic Division: Promotes a calming state, supporting digestion and energy conservation; lowers heart rate and blood pressure.

Neurons

Basic structural and functional units of the nervous system.
Cell Body (Perikaryon): Central portion responsible for metabolism and gene expression.
Dendrites: Tree-like structures conducting impulses to the cell body.
Axon: Transmits nerve impulses away from the cell body.

The Brain

Control center of the nervous system, weighing about 3 pounds, with a structure that is soft, spongy, and pinkish gray.
Composed of over 100 billion neurons and demands continuous oxygen and glucose supply.
Major components include:
- Brain Stem
- Cerebrum
- Cerebellum

Brain Development

Begins during the 4th week of embryonic development, forming three major vesicles:
- Prosencephalon (Forebrain): Divides into Telencephalon (cerebrum) and Diencephalon (thalamus, hypothalamus).
- Mesencephalon (Midbrain)
- Rhombencephalon (Hindbrain): Divides into Metencephalon (cerebellum, pons) and Myelencephalon (medulla oblongata).

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on the fundamental components and functions of the human nervous system. This quiz covers various aspects including structure, organization, and the role of neuroglia. Perfect for students studying biology or health sciences.