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A&P Ch9 Nervs.Tissue
Anatomy & Physiology: Ch9 Nervous Tissue
Question | Answer |
---|---|
What are the structures that make up the Nervous System? | brain, cranial nerves and their branches, spinal cord, spinal nerves and their branches, ganglia, enteric plexuses, and sensory receptors. |
How many neurons in the brain? | 100 billion. |
How many cranial nerves emerge from the base of the brain? | 12 pairs (right and left), numbered I through XII. |
What is a nerve? | A bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels that lie outside the brain and spinal cord. |
What are the three basic functions of the Nervous System | 1. sensory function 2. integrative function 3. motor function |
Nervous System, Sensory Function | sensory receptors detect internal stimuli (ex. increase blood acidity) and external stimula (ex. raindrop touch skin). This sensory info is carried into the brain and spinal cord through cranial and spinal nerves. |
Nervous System, Integrative Function | Sensory information is integrated by analyzing and storing some of it and by making decisions for appropriate responses. An important Integrative Function is PERCEPTION (conscious awareness of sensory stimuli), which occurs in the brain. |
Nervous System, Motor Function | After sensory information is integrated, the NS may elicit an appropriate motor response by activating EFFECTORS (muscles and glands) through cranial and spinal nerves, causing muscles to contract and glands to secrete. |
Spinal Cord | connects to brain, encircled by bones of vertebral column, contains 100 million neurons. |
Spinal Nerves | 31 pairs emerge from spinal cord, each serving region on right or left side of body. |
Ganglia | small masses of nervous tissue (mostly neuron cell bodies) located outside but closely related to the brain and spinal cord. |
Enteric Plexuses | extensive networks of neurons, located in the walls of the gastrointestinal tract, that help regulate the digestive system. |
The two main subdivisions of the Nervous System are? | 1. Central Nervous System (CNS)= brain and spinal cord 2. Peripheral Nervous System (PNS)= all nervous tissue outside CNS |
What are the 3 parts of a Neuron? | 1. Cell body = contains nucleus, cytoplasm, etc. 2. Dendrites = a process that emerges from 1; receiving or input parts of a neuron. 3. an Axon = a process that emerges from 1; conducts nerve impulses toward another neuron, muscle fiber, or gland cell. |
What is an Axon Hillock? | A cone shaped elevation where the long cylindrical projection of an axon joins the cell body. |
What is an Axon Collateral? | Axon side branches. |
What are Axon Terminals? | Where axons and axon collaterals divide into many fine processes, and so, end. |
What is a Synapse? | The site where two neurons or a neuron and an effector cell can communicate. |
What is a Synaptic End Bulb? | What the tips of most axon terminals swell into. |
What are Synaptic Vesicles? | Tiny sacs that store chemicals (neurotransmitters), located inside the Synaptic End Bulbs. |