Name the two main nervous tissue cells
Neuroganglia and neurons
FUNCTION of nervous system
To control an integrate activities in the body as it reacts to conditions in its internal and external environments.
Organization of nervous system
- Central nervous system (CNS) (head and spinal cord) and peripheral nervous system (PNS) (everything else)
- Somatic nervous system (SoNS)
- Autonomic nervous system (ANS)
SoNS
Signals to/from skeletal muscle-tendon-skin. Crosses between CNS and PNS. Skeletal muscle, voluntary movements (mostly)
ANS
Signals to/from viscera (muscle/glands in heart, lungs, gut, other) Crosses between CNS and PNS. Gland, smooth-cardiac muscles (involuntary movements). Breaks down further into Sympathetic, Parasympathetic, and Enteric
CNS
Processes sensory input, initiates responses, thought-emotion-memory
Spinal cord
Connections of brain and periphery, controls reflexes
Enteric Nervous System (ENS)
GI nervous system (regulated by ANS (autonomous)
ANS Divisions
- Sympathetic (fight or flight)
- Parasympathetic (Rest and digest. Dine and recline)
- Enteric (GI Functions)
Neurons
Conductive. Contains cell body and processes. Dendrites and axon. Different types of them
Neuroganglia
Supportive. 5x more numerous than neurons. Different types of this
Describe pathway of prenatal origins of nervous cells
- Ectoderm
- Neuroectoderm
- Splits into neural tube neuroepithelium and migrator neural crest
- The neural tube neuroepithelium becomes neurons and neuroganglia of CNS while the migratory neural crest becomes neurons and neuroganglia of PNS
Neural tube forms:
CNS and its cells
Neural crest forms
PNS and its cells
Types of neuroganglia
- For CNS: oligodendrocytes, astrocytesm ependymal, microglia
- PNS: schwann cells and satellite cells.
NOTE: Connective tissue and Schwann cells allow for potential axon repair after injury in the PNS
Name the 4 neuron types
- General somatic sensory/afferent (pseudounipolar)
- Autonomic visceral sensory/afferent (pseudounipolar)
- General somatic motor/efferent (multipolar)
- Autonomic visceral motor/efferent (multipolar)
Pathway of signal and drug used
Somatic motor neuron CNS: Uses Ach to contact PNS, which triggers effectors
Sympathetic (presynaptoic /preganglionic autonomic motor neuron uses Ach to contact postganglionic/postsynaptic autonomic motor neuron. On the post end, it used adrenergic drugs to relay message
Parasympathetic is the same as sympathetic, but both pre and post use Ach. Both Sympathetic and parasympathetic trigger cardiac muscl, smooth muscle, and glands
Synapse
Where neurotransmitters are released from neurons and bind receptors on membranes of neurons/effectors
Gray matter
Neuron cell bodies
White matter
Myelinated axons
Neuron cell body clusters
Nuclei (gray matter) or ganglia (PNS). Same thing.
Axon bundles
Tracts in CNS (white matter) or nerves in PNS (myelinated-unmyelinated)
