Test 4 Flashcards
What are the functions of the nervous system ?
- Maintaining homeostasis: the cells in the body must work together to maintain homeostasis
- Receiving sensory input : sensory receptors monitor numerous external & internal stimuli. Sensations from stimuli include all 5 senses
- Integrating information: the brain & spinal cord are the major organs for processing sensory input & initiating responses.
- Controlling muscles and glands: skeletal muscles normally contract only when stimulated by the nervous system, thus the NS controls major movement of body
- Establishing & maintaining mental activity: the brain is the canter of mental activities, including consciousness, thinking, memory and emotions.
What are the divisions of the nervous system?
Components which are the: brain, spinal cord, nerves, sensory receptors
And the subdivisions which are:
- Central nervous system ( brain, spinal cord)
- peripheral nervous system: sensory receptors and nerves
What are the cranial nerves?
They originate from the brain, 12 pairs
What are spinal nerves ?
Originate from the spinal cord, 31 pairs
What is ganglion?
Collection of Neuton cell bodies outside CNS
What are sensory receptors ?
The ending of neurons or separate, specialized cells that detect temperature, pain, touch , pressure, light , sound and odours
What is plexus?
Extensive network of axons located outside the CNS
Sensory ( AFFERENT):
transmits action potentials from receptors to CNS
Motor ( EFFERENT):
Transmits action potentials from CNS to effectors ( muscles, glands )
Explain the somatic nervous system:
- from CNS to skeletal muscles
- voluntary
- single neuron system
- synapse : junction of a nerve cell with another cell
Explain the autonomic nervous system (ANS) :
- from CNS to smooth, cardiac muscle and certain glands
- subconscious or involuntary control
- two neuron systems: first from the CNS to ganglion, second from ganglion to effector
What are the divisions of the autonomic nervous system?
- sympathetic: prepares body for physical activity
- parasympathetic: regulates resting or vegetating functions such as digesting food or emptying of the urinary bladder
- enteric: plexuses within the wall of the digestive tract, can control the digestive tract but still considered part of the ans because of the parasympathetic and sympathetic neurons that contribute
Cells of the nervous system
- Neuroglia: suppers and protects neurons
- Neurons or nerve cells: receive stimuli and transmit action potentials
What is the organization of the Neuron
- Cell body or soma
- dendrites: input
- axons: output
What is the blood brain barrier ?
Protect neurons from toxic substances
What is a Schwann cell/ neurolemmocytes?
Wrap around portion of only one axon to form myelin sheath
What is a satellite cell?
Surround neuron cell bodies in sensory ganglia, provides support and nutrients
What is a myelinated axon?
Myelin protects and insulates axons from one another
What is the nodes of ranvier??
- a gap occurring at regular intervals between segments of myelin sheath along a nerve axon.
Explain unmylinated axons
- Not wrapped around the axon
- Gray matter
List the organization of the nervous tissue
- gray matter: unmylinated axons, cell bodies, dendrites, Neuroglia,
- white matter : myelinated axons, nerve tract propagate action potentials from one area in the CNS to another
In brain: gray is outer cortex as well as inner nuclei, white is deeper
In spinal cord: white is outer, gray deeper
What are electrical signals
- cells produce electric signals called action potential
- transfer of info from one part of body to another
- electrical properties result from ionic concentration differences across plasma membrane and permeability of membrane
Explain synapse
- junction between two cells
- site where action potentials in one cell cause action potentials in another cell
What are the two types of cells in synapse
- pre synaptic
- post synaptic
