Chapter 6 Flashcards
Nervous System characteristics
-Fast acting
-Electrical impulses
(As opposed to endocrine system)
-Derived from Neural (plate) Ectoderm, or Neural Crest Ectoderm
Two types of Nervous Syste,
CNS, PNS
CNS
Central Nervous System (CNS) = brain and spinal cord (dorsal hollow nerve cord)
neural plate ectoderm
PNS
Peripheral Nervous System = all nerves that exit or enter the CNS (always paired, right and left)
neural crest ectoderm
crainal nerves,
Functional Division
Somatic vs. Visceral
somatic afferent
carry sensory impulses to the CNS from skeletal muscle, from skeletal muscle to the brain
somatic efferent (ex)
motor output from CNS to Skeletal Muscles (Voluntary) push them away from you
visceral afferent
carry sensory impulses to the CNS from blood vessels or internal organs, from organs to the brain
visceral efferent
involves a preganglionic and postganglionic neuron and travels to smooth muscle, cardiac muscle and glands, autonomic motor output to internal organs and glands
somatic (concious) nervous system
Sensory (afferent) nerves receive input from:
- Body wall (skin, musculature)
- Appendages
- Motor nerves (efferent) send messages to musculature of body wall (somatopleure-made of ecto and meso)
visceral (unconcious) nervous system
Visceral Sensory:
Receive signals from organs of splanchnopleure(from meso-endo) also a bit of an ectoderm from this nervous system (hunger, discomfort, full bladder, some taste, some smell) unconcious signal to brain to you
Visceral Motor - automatic nervous system (8 lecture)
organization of the nervous system
Somatic nervous system also splits into two
- Somatic afferent
- Somatic efferent
Basic facts about Neurons
- They have ability to respond to stimuli. (change in cell membrane, they can take that change and create a signal)
- They have ability to CONDUCT AN ELECTRICAL SIGNAL.
SIGNAL PATHWAYS
Something causes change in property of neuron cell membrane.
This causes an electrical signal to enter cell, usually via dendrite(s). on or near cell body.
Travel along cell.
Usually leave via axon. SIGNAL DEGRADATION(lost of strength) IS REPRESSED DUE TO INSULATION BY MYELIN.
INSULATION OF NEURONS
To prevent electrical charge and current from “leaking out”, axons are insulated by a special type of material called MYELIN. electerial and physical border
-preventing electerical charge for leaking out
SCHWANN CELLS.
In PNS, myelin is produced by neuroGLIAL cells called
only happens in specific sports
OLIGODENDROCYTES.
In CNS, myelin is produced by neuroGLIAL cells called
only happens in specific spots
can cover
neurofibral NODES
Layers of myelin are wrapped around most of axon. Unlike that of an electrical cord, the covering is not continuous. These brief interruptions are called neurofibral nodes
at node, you can access the axolemma, ions can move
GANGLION (plural = ganglia)
(Frequently) cell bodies are concentrated in a spot along a nerve, forming a swelling called a
NUCLEUS
In the CNS, a collection of cell bodies is called a
What is said to be POLARIZED
The plasma membrane (cell membrane)
Nervous System divides
into CNS PNS
CNS
brain/spinal cord
PNS
somatic, visceral