Flashcards in Nervous Tissue/Brain; Blood supply to Brain (Ch. 14-15, 23.3) Deck (81)
What does the nervous system (NS) include?
All neural tissue in the body (neurons and glial cells)
What is included in the central nervous system (CNS)?
What is included in the peripheral nervous system (PNS)?
All neural tissue outside the CNS
What are NS fxns?
--monitor external and internal changes (sensory input from PNS)
Process and evaluate information
--process sensory input and determines response
Respond to information
--dictates response by activating effector organs
What are the 2 divisions of the NS?
What is the functional organization of the NS?
NS branches into: Sensory NS and Motor NS
Sensory NS branches into: Somatic Sensory and Visceral Sensory
Motor NS branches into: Somatic Motor and Autonomic Motor
What is Somatic Sensory?
Free nerve endings in almost all body tissues
Includes receptors for pain, touch, pressure, vibration, temperature...
Also proprioception (sense of body in space) in skin, body wall, and limbs
"Special" senses = vision, taste, hearing, balance, smell
What is Visceral Sensory?
Sensations from the organs (digestive and urinary tracts, reproductive organs, etc.)
What is Somatic Motor?
aka Voluntary NS (b/c we can control it)
--motor nerves carry impulses from the brain to the skeletal muscles and somatic tissues, which creates voluntary movement
Contraction of skeletal muscles
What is Autonomic Motor?
aka Autonomic NS (ANS) or involuntary nervous system
Regulates contraction of smooth and cardiac muscle and gland secretion
We cannot control this
Subdivides into sympathetic and parasympathetic
What is Sympathetic (under ANS)?
"fight or flight"
What is Parasympathetic (under ANS)?
"resting and digesting"
What are the 2 types of cells in nervous tissue?
Neurons and Glia
What are neurons?
Neurons transmit electrical signals
What are glia?
What is included in the structure of a neuron?
Soma (cell body)
Structure of a Neuron: what are soma?
Contains nucleus, cytoplasm, organelles
Structure of a Neuron: what are dendrites?
receive signal, transmit to cell body
Structure of a Neuron: what are axons?
transmits signal to axon terminals (note direction of signal movement)
Structure of a Neuron: what is myelin?
Insulates neuron, helps propagate signal
Describe the signal pathway of dendrites and axons.
Dendrite --> cell body --> axon --> axon terminal (end of axon)
What is a synapse?
A synapse is a site where an axon connects with another cell (another neuron cell or muscle and gland cells)
What are the 4 types of Glia (of the CNS)?
1. ependymal cells
In general, glia support and protect the neurons. Each type has slightly different functions though (*do NOT need to know functions for lecture exam)
What are Schwann cells? What are Satellite cells? Where are they found?
Found in Glia of the PNS
Schwann cells: myelinate axons of PNS
Satellite cells: found in ganglia, surround the neuron cell body
What are nerves?
A nerve is defined as a collection of axons in the PNS
The axons are arranged in parallel and wrapped in CT
A nerve can contain myelinated and/or non-myelinated, sensory and/or motor axons
What is included in the structure of a nerve?
Myelin sheath, Axon, Fascicle
Each axon is surrounded by myelin sheath (Schwann cells)
Groups of axons are nerve fascicles
Groups of fascicles = nerve
What are the 3 layers of nerve structure (from superficial to deep)?
1. Epineurium: surrounds entire nerve
2. Perineurium: surrounds fascicle
3. Endoneurium: surrounds axon and myelin sheaths
What 3 things protect the brain?
Cerebrospinal fluid (CSF)
Blood brain barrier (BBB)
What are meninges?
They're membranes that surround and protect the brain