Introduction to the nervous system

When a receptor is stimulated by an environmental change, it will cause the sensory neuron to

depolarize

These spinal nerves are responsible for segments of the body called ___________

dermatomes

TRUE OR FALSE: Motor neurons are a part of the nervous system

false

areas in the CNS with lots of synapses are referred to as ________

gray matter

propioreceptors

monitor positions of joints and skeletal muscles

________ neuron that will carry the message out of the CNS to an ___________ (causing the muscle to contract or the gland to secrete)

motor, effector

Function of Schwann cells

produce myelin in PNS;aid in regeneration of damaged nerve fibers

What detects changes in the environment?

receptors

Divisions of Peripheral Nervous System (4)

receptors sensory and motor neurons nerves ganglia

neuron to exocrine gland cell forms a

neuroglandular junction

neuron to muscle cell forms a

neuromuscular junction

Axons are often covered with a fatty myelin sheath with gaps called ___________

nodes of ranvier

Subdivisions of autonomic/visceral system (2)

parasympathetic sympathetic

Autonomic/visceral division

sensory information from internal receptors in organs (heart, stomach), BP, body temp, blood levels of O2 & CO2, pH. Motor information to involuntary effectors (smooth and cardiac muscles only)

Receptors are attached to

sensory neurons

function division of peripheral nervous system (2)

somatic autonomic

In general, if the effector is below the head (e.g. muscles for waving or kicking), the motor neuron will leave the CNS from the _________

spinal cord

Sensory neurons that carry messages into the spinal cord and motor neurons that carry messages out of the spinal cord can be found in structures called _______

spinal nerves

Sensory neurons that carry messages into the spinal cord and motor neurons that carry messages out of the spinal cord can be found in structures called __________ _________

spinal nerves

Which division speeds up the heart during an emergency and with what hormone?

sympathetic, norepinephrine

When a sensory neuron brings a message into the CNS from a receptor, it forms a ____________ with an interneuron

synapse

neuron to neuron forms a

synapse

what system organizes and interprets information?

the central nervous system

Interneurons traveling together from spinal cord to brain, from brain to spinal cord or from one part of the brain to another part of the brain can be found in structures called _______

tracts

T or F: Only spinal nerves have dermatomes

true

The axon may have branches called ________ with its own axon terminals carrying vesicles with neurotransmitter

axon collaterol

tracts consist of

collections of interneurons

ganglia

collections of somas/synapses found outside the CNS

Sympathetic division

controls involuntary effectors during emergencies, "fight-or-flight" activities Neurotransmitter is norepinephrine (NE)

parasympathetic division

controls involuntary effectors during normal activities (calming effects) Neurotransmitter is acetylcholine (ACh)

Sensory neurons carrying messages into the brain and motor neurons carrying messages out of the brain can be found in structures called ______ _______

cranial nerves

Sensory neurons carrying messages into the brain and motor neurons carrying messages out of the brain can be found in structures called ___________

cranial nerves

how many cranial nerves are there?

12 pairs

What many spinal nerves are there?

31 pairs

There are _____ cervical spinal nerves (C__-C___), ___ thoracic spinal nerves (T___-T____), __ lumbar spinal nerves (L__-L___), ___ sacral spinal nerves (S__-S___) and 1 coccygeal nerve (Co1).

8, (C1-C8) 12, (T1-T12) 5, (L1-L5) 5, (S1-S5)

Once the emergency passes, ___ from the ______ nerves will speed up digestion back to normal

ACh, parasympathetic

6 types of glial cells

CNS: 1. astrocytes 2. microglial cells 3. ependymal cells 4. oligodendrocytes PNS: 1. Schwann cells 2. satellite cells

function of astrocytes

Cover brain surface and nonsynaptic regions of neurons; form supportive framework in CNS; induce formation of blood-brain barrier; nourish neurons; produce growth factors that stimulate neurons; promote the formation of synapses and neural circuitry; communicate electrically with neurons and may influence synaptic signaling; remove K+ and some neurotransmitters from ECF of brain and spinal cord; help to regulate com- position of ECF; form scar tissue to replace damaged nervous tissue

function of oligodendrocytes

Form myelin in brain and spinal cord

function of ependymal cells

Line cavities of brain and spinal cord; secrete and circulate cerebrospinal fluid

During an emergency, __ from ______ nerves will slow down digestion

NE, sympathetic

What division slows down the heart back to normal and with what neurotransmitter?

Parasympathetic, ACh

function of microglial cells

Phagocytize and destroy microorganisms, foreign matter, and dead nervous tissue

function of satellite cells

Surround somas of neurons in the gan- glia; provide electrical insulation and regu- late chemical environment of neurons

somatic division

Sensory information from external receptors in skin (touch, pressure, pain, Temperature), muscles, joints (proprioceptors), etc. Motor information to voluntary effectors (skeletal muscles only)

If the effector is in the head (e.g. chewing muscles or salivary gland), the motor neuron will leave the CNS from the ______ (there are exceptions).

brain

Divisions of the central nervous system (4)

brain and spinal cord Tracts and nuclei

What directs appropriate responses? Where are they found?

effectors, found in muscles and glands

When myelinated axons in the CNS are found next to each other in tracts (carrying messages from spinal cord to brain, brain to spinal cord or from one part of the brain to another), these tracts are referred to as ________

white matter