Nervous System (intro)

SBI4U - Howes

What is the function of the nervous system?

the coordinating centre for homeostasis

to carry out its function, __________ send info into the nervous system, which sends info to __________ to make the appropriate change.

sensors, effectors

the nervous system is divided into two parts:

Central nervous system (CNS) & Peripheral nervous system (PNS)

What makes up the Central Nervous System?

• brain

• spinal cord

the spinal cord’s role in the Central Nervous System:

conducting signals to and from the brain and controlling reflex activities

the Peripheral Nervous System has two kinds of _________: _____ and ________

NEURONS, motor, sensory

Motor Neurons

carry signals from CNS → muscles and glands

Sensory Neurons

carry signals from sensory organs → CNS

depending on what they control, Motor Neurons can be either ___________ or ___________.

somatic, autonomic

Somatic vs Autonomic motor neurons

• Somatic: controls voluntary movements

• Autonomic: controls involuntary movements

the Autonomic Nervous System is divided into 2 divisions: ______________ and ________________

sympathetic, parasympathetic

Sympathetic vs Parasympathetic Divisions of the Autonomic NS

• Sympathetic: triggers “fight or flight” response (↑ heart rate, alertness…)

• Parasympathetic: activates “rest and digest” function (promotes relaxation, recovery…)

Neurons are the ___________ _____ of the __________ system. There are __ main types of neurons.

functional unit, nervous, 3

3 main types of neurons

1. Afferent Neurons (aka sensory): relay info from environment → CNS

2. Efferent Neurons (aka motor): relay info from CNS → effectors

3. Interneurons: link sensory and motor neurons, integrate and interpret sensory info

Where are interneurons found?

brain and spinal cord

Glial Cells

non-conducting cells whose function is to support neurons

Neural Circuit (also name the 5 components)

the coordination of 5 components — sensor, afferent neuron, interneuron, efferent neuron, effector — in response to a stimulus

the _________ neural circuit is the ________ ____

simplest, reflex arc

reflex arcs are very ____ because they don’t require the ____ to make a decision

fast, brain

Label the general structures of a neuron

1. Axon Terminals (tip: Terminals look like Tails)

2. Myelin Sheath

3. Axon

4. Cell Body (aka Soma)

5. Nucleus

6. Dendrites

what is the role of axon terminals in a neuron cell?

to interact with the dendrites of another neuron

the cells that make up the myelin sheath are a type of _____ cell called ________ ______.

glial, schwann cells

the _____ in between sections of the ________ _________ are called the _______ of __________.

gaps, myelin sheath, nodes of Ranvier

what is the role of dendrites in the neuron?

to grab and receive info from another neuron

“dendrites recieve it right” 👍