2 - APP - Unit 3.1 - Nervous System Flashcards
The nervous system
Controls and coordinates the functions of the other systems of the body so they work harmoniously and efficiently.
Composed of: brain + spinal cord + peripheral nerves
The nervous system - Types of cells
- Neurons
- Neuroglia
The nervous system - Neurons
Responsible for most special functions attributed to the nervous system:
- sensing
- thinking
- remembering
- controlling muscle activity
- regulating glandular secretions
The nervous system - Neuroglia
Support, nurture and protect neurons and maintain homeostasis of the fluid that bathes neurons
Neurons & nerves - Neuron composition
A cell body
Its outgrowth of projections (=neuronal fibers)
Neurons & nerves - Types of neuronal fibers
- Numerous multi-branched dendrites that connect with other neurons to receive information
- A single Axon that conducts impulses away from the cell body
Neurons & nerves - Cell body
Stores energy and nutrients that are used by the cellular projections to receive and conduct nerve impulses throughout the body
Neurons & nerves - Synapse
Junction at which impulses are passed from one neuron to another
Neurons & nerves - Neurotransmitter
When an impulse reaches the end of an axon, a chemical neurotransmitter is released at the synapse that acts on the membrane of the receptive neuron to pass the impulse along.
Neurons & nerves - Neurons are classified according to…
… the direction in which they transmit nerve impulses and the type of information carried.
Neurons & nerves - 3 types/classifications of neurons
- Sensory neurons
- Motor neurons
- Interneurons
Neurons & nerves - Sensory neurons
AKA Afferent Neurons
Originate in the periphery of the body
Carry incoming information (impulses or messages from sense organs) to the brain & spinal cord where sensations of touch, cold, heat, sight, hearing, taste or pain are interpreted and experiences
Neurons & nerves - Motor neurons
AKA Efferent Neurons
Carry outgoing motor information (nerve impulses) from the brain/spinal cord to the muscles or glands that they control
Neurons & nerves - Interneurons
AKA Central or Connection neurons
Located in the brain and spinal cord
Carry impulses from one neuron to another
Neurons & nerves - Nerve cell bodies & fibers location
Almost all nerve cell bodies are contained in the brain and spinal cord
Fibers extend outward to make up the nerves
Neurons & nerves - Nerve
A group of neuronal fibers (axons and/or dendrites) found in the peripheral portions of the nervous system bundled together by connective tissue like the strands of a cable
Neurons & nerves - Myelin
Fatty insulating material wrapping individually the fibers found within the nerve
Divisions of the Nervous System - 2 divisions
- Central nervous system
- Peripheral nervous system
Divisions of the Nervous System - Central nervous system (CNS)
CNS = Brain + Spinal Cord
- incoming sensory information are integrated and correlated
- thoughts and emotions are generated
- memories are formed and stored
Originate in the CNS: most nerve impulses that stimulate muscles to contract & glands to secrete
CNS communicates with rest of the body through PNS
Divisions of the Nervous System - Brain
Principle nerve center
Body’s largest & most complex nerve tissue containing in excess of ten billion neurons and innumerable nerve fibers
Located in & protected by cranium
Controls sensations, muscles, glandular activity & the power to think and feel (emotions)
Divisions of the Nervous System - Brain - Diencephalon
2 parts:
- Thalamus - the “sensory brain”
- Hypothalamus - the principal link between endocrine and nervous systems
Divisions of the Nervous System - Brain - Cerebrum
Largest portion making up the front and top of the brain Presides over complex activities / mental activities as: - speech - sensation - communication - memory - reasoning - emotions
Divisions of the Nervous System - Brain - Cerebellum
Smaller part of the brain
Located below the cerebrum & at the back of the cranium
Helps maintain body balance, coordinates voluntary muscles & makes muscular movement smooth and graceful
Divisions of the Nervous System - Peripheral nervous system (PNS)
PNS = All the nerves that connect the central nervous system to the rest of the body
Includes cranial nerves, spinal nerves and their branches