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Lecture 4

HSCI 1130 Lecture Notes - Lecture 4: Neuroglia, Primary Cell, Water Content


Department
Health Sciences
Course Code
HSCI 1130
Professor
Blake
Lecture
4

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Homeostasis:
State of equilibrium or balance
Humans must maintain their internal environment within certain limits
Temperature
Acidity(Ph 7.4-7.6)
Water content
Sodium content
Glucose concentration
Other physical and chemical factors
Components of the nervous system:
Nervous system is composed of two primary cell types
Glial cells
Neurons
Glial cells:
Glial cells or glia (10-50X as many glia as neurons)
Provide firmness and structure
Get nutrients in the system
Eliminate waste
Form myelin
Create the blood-brain barrier
Communicate with other glia and neurons
Nerve cells (neurons)
Analyze and transmit information into brain
4 defined regions:
Cell body
Dendrites
Axon
Presynaptic Terminals
Stimulation of receptors by psychoactive drugs can activate or inhibit a neuron
Chapter 4 The nervous system
Thursday, February 01, 2018
4:29 PM

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Stimulation of receptors by psychoactive drugs can activate or inhibit a neuron
*Neuron image here*
Each of these defined regions contribute to the neurons ability to communicate with
other neurons, and psychoactive drugs exert effects within each of these regions.
Neurotransmission:
Action potential
a brief electrical signal transmitted along the axon
Neurotransmitters are the chemical "messengers"
Resting action potential is caused by uneven distribution of ions
Action potential occurs when sodium ions move across channels
Blocking channels prevents the action potential and disrupts communication
between neurons (numbing cream)
Action Potential Figure 4.4 in text book
Positive and negative effects of action potential
Polarization: resting potential is negative
Depolarization: overshoot phase, action potential is reached , very positive
Hyperpolarization: undershoot phase, returning to homeostasis initially very
negative
The nervous system:
1)Somatic nervous system: (soma=body)
Sensory information: (sight, smell, touch, hear, taste)
Voluntary actions: (movement)
2)Autonomic nervous system (ANS): Automatic
Sympathetic branch:
Parasympathetic branch :
3)Central nervous system(CNS):
Brain:
Spinal Cord:
Somatic nervous system:
Carries sensory information into the central nervous system
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Carries sensory information into the central nervous system
Carries motor (movement) information back out to the peripheral nerves
Control Voluntary actions
Acetylcholine(movement) is the neurotransmitter at neuromuscular junction
Autonomic nervous system:
Monitors and controls the body internal environment and involuntary functions
Many psychoactive drugs effect the brain and the autonomic nervous system
Two branches often act in opposition (we need both)
Sympathetic branch (fight or flight) release of cortisol, moving blood to....
Parasympathetic branch (rest and digest)
Table 4.1 in text book
Central nervous system:
Consists of the brain and the spinal cord
Has many functions
Integration of information
Learning and memory
Coordination of activity (motor)
The Brain:
Cerebral cortex: Executive function nd ability to make rational decision,
integration of different sensations into movement/action
Basal ganglia: muscle tone
Hypothalamus: Initiates the release of hormones/neurotransmitters
Limbic system: Emotional part of the brain
Midbrain, pons, and medulla (brain stem): staying alive, heart pumping and
breathing
The Brain:
Basal ganglia: subcortical brain structures controlling muscle tone
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