Chapter 11 Highlights Flashcards
Anatomical divisions of the nervous system
- Central nervous system
- Peripheral nervous system
Central nervous system
Brain and spinal cord
Brain
- Billions of nerve cells
- Protected by bones of skull
Spinal cord
- Begins at foramen magnum
- Continues through vertebral foramina of cervical to first or second lumbar vertebra
- Millions of neurons, fewer than brain
- Enables brain to communicate with most of body below head and neck
Peripheral nervous system
All nerves in the body outside the protection of the skull and vertebral column
Nerves
- Axons of neurons bundled together with blood vessels and connective tissue
- Carry signals to and from CNS
- Classified by origin or destination
Cranial nerves
12 pairs of nerves traveling to or from brain
Spinal nerves
1 pair of nerves traveling to or from the spinal cord
Functional divisions of the nervous system
- Sensory
- Motor
Sensory (afferent) nervous system
- Gathers info about internal and external environments
- Carries signals from receptors to the spinal cord and the brain
Divisions of afferent division
- Somatic sensory division
- Visceral sensory division
Somatic sensory division
- Special sensory division
- Carries signals from skeletal muscles, bones, joints, and skin, organs of vision, hearing, taste, smell, and balance
Visceral sensory division
Transmits signals from heart, lungs, stomach, kidneys, and urinary bladder
Divisions of efferent division
- Somatic motor division
- Autonomic nervous system
Somatic motor division
- Neurons transmit signals to skeletal muscle
- Voluntary control
Autonomic nervous system
- Neurons carry signals to thoracic and abdominal viscera
- Critical for maintaining homeostasis
- Regulates secretion of certain glands, contraction of smooth muscle and cardiac muscle
- Involuntary
Neurons
Excitable cells responsible for sending and receiving signals as action potentials
Parts of a neuron
- Cell body (soma)
- Dendrites
- Axon
Soma
- Most metabolically active region
- Manufactures proteins
Dendrites
- Short, branched processes
- Receive input from other neurons
Axon
Generate and conducts action potentials
Axon hillock
Where axon originates from cell body
Axon terminals
- Synaptic bulbs
- Components that communicate with target cell
Interneurons
Relay info within CNS b/t sensory and motor neurons
Neuroglial cells
- Astrocyte
- Oligodendrocyte
- Microglial cell
- Ependymal cell
- Schwann cells
- Satellite cells
Function of Astrocyte
- Anchor neurons and blood vessels
- Regulate the extracellular environment
- Facilitates the formation of the blood brain barrier
- Repair damaged tissue