What body parts make up the central nervous system? Brain and Spinal Cord BELL RINGER.

What body parts make up the central nervous system?

Brain and Spinal Cord

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UNIT #3: BIOLOGICAL BASES OF BEHAVIOR

MODULE #4: NEURAL AND

HORMONAL SYSTEMS

Franz Gall invented phrenology – the theory that bumps on our skull could reveal our mental abilities and character traits.

PHRENOLOGY

Stupid as it was, it did lead us to realize that different parts of our brains have various particular functions.

Neuropsychologists are explore relationships between brain/nervous systems and behavior.

Also called biological psychologists and biopsychologists, they study the link between biology and psychology.

NEUROPSYCHOLOGISTS

Neuron: a nerve cell; the basic unit of structure and function of your nervous system.

Three major functions: receive information, process it, and transmit it to the rest of your body.

STRUCTURE AND FUNCTION OF THE NEURON

Cell body (cyton or soma): contains cytoplasm and the nucleus, which directs synthesis of neurotransmitters.

Nucleus: holds all the genetic information of the cell.



Cell Body

Nucleus

Dendrites: the branching extensions of a neuron the receives messages and sends impulses to the body.

Axon: the extension of a neuron through which messages pass to other neurons or to muscles or glands.

Axon Terminal: tip of the axon



Dendrites

Axon

Axon Terminal Cell Body

Nucleus

myelin sheath: fatty tissue that insulate the axon and speeds up transmission.

node of Ranvier: gaps between the myelin sheaths.

Schwann’s cells: cells that create myelin.



Dendrites

Axon

Myelin Sheath

Axon Terminal

Schwann’s Cells

Cell Body

Nucleus

Node of Ranvier

Excitatory signal neurons to go, while inhibitory signal them to stop.

If excitatory minus inhibitory exceeds a minimum threshold, an action potential (neural impulse) is triggered.

Action potential: a neural impulse; a brief electrical charge that travels down an axon.


If your stimulation is not strong enough, your neuron does not fire.

The strength of the action potential is constant whenever it occurs.

This is called the “all-or-none principle.”


Synapse: the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. This gap at this junction is called a synaptic gap or cleft.


Neurogenesis: growth of new neurons that takes place throughout life.


neurotransmitters: chemical messengers that travel synaptic gap between neurons.

They are released by one neuron and bind to the receptor sites on the receiving neuron.

Extra neurotransmitters are sent back to the sending neuron in a process called reuptake.

Used by neurons to communicate with each other.


Neurotransmitter

Function

Too Much:

Too little:

NEUROTRANSMITTERS

Make a chart like this in your notes. We will go through some neurotransmitters. Fill in the chart as we go along.

Acetylcholine (ACh) causes contraction of skeletal muscles, helps regulate heart muscles, is involved in memory, and also transmits messages between the brain and spinal cord.

Lack of ACh is associated with Alzheimer’s disease.

NEUROTRANSMITTERS

Neurotransmitter

Function Too Much

:

Too little:

acetylcholine (ACh)

muscle movement, memory, transmits messages between brain & spinal cord

n/a Alzheimer’s disease

NEUROTRANSMITTERS

dopamine: stimulates the hypothalamus to synthesize hormones and affects alertness and movement.

Lack of dopamine is associated with Parkinson’s disease.

Too much is associated with schizophrenia.

NEUROTRANSMITTERS

glutamate: excitatory neurotransmitter involved in information processing throughout the cortex and especially memory formation in the hippocampus.

Too much: Alzheimer’s diseaseToo little: Schizophrenia

NEUROTRANSMITTERS

Serotonin: associated with sexual activity, concentration and attention, moods, and emotions.

Lack of serotonin is associated with depression.

NEUROTRANSMITTERS

Gamma-Aminobutyric Acid (GABA): inhibits the firing of neurons.

Too little: Huntington’s disease (associated with insufficient GABA-producing neurons in parts of the brain involved in the coordination of movement)

Too much: associated with seizures

NEUROTRANSMITTERS

Endorphins: natural opiate, body’s painkiller.

Too little is associated with addiction withdrawal.

NEUROTRANSMITTERS

Other chemicals (drugs like heroine and morphine) can interfere with the action of neurotransmitters.

Agonists: may mimic a neurotransmitter and bind to its receptor site to produce the effect of the neurotransmitter.

Antagonists: block a receptor site inhibiting the effect of the neurotransmitter or agonist.

NEUROTRANSMITTERS

All of the neurons in your body are organized into your nervous system.

The two major subdivisions are the central nervous system (CNS) and the peripheral nervous system (PNS).

ORGANIZATION OF YOUR NERVOUS SYSTEM

Central Nervous System (CNS): made up of the brain and spinal cord.

Spinal cord: starts at the base of your back and extends upward to the base of your skull where it joins your brains.


Info travels through 3 types of neurons:

Sensory neurons: sends information from body’s tissues and sensory organs to brain and spinal cord.

Motor neurons: sends information out from brain/spine to body.

Interneurons: communicates between sensory and motor neurons.


Peripheral Nervous System (PNS): made up the somatic and autonomic nervous systems, and connects the CNS to the rest of your body.

Somatic Nervous System: Controls the body’s skeletal muscles.

Autonomic Nervous System: Controls the glands and the muscles of the internal organs.


The Autonomic Nervous System is divided into two parts:

Sympathetic Nervous System: Responses that help your body deal with stressful events, including:

Accelerate your heart beat, raise your blood pressure, slow your digestion, raise your blood sugar, activate your sweat glands, which makes you alert.


The Autonomic Nervous System is divided into two parts:

Parasympathetic Nervous System: Calms your body to conserve energy.

Comes after sympathetic system restoring digestive processes, returning pupils to normal size, restoring normal bladder contractions, slow breathing and heart rate, etc.


Nervous System

Peripheral Nervous System

Central Nervous System

Spinal Cord

Autonomic Nervous System

Somatic Nervous System

Sympathetic Nervous System

Parasympathetic Nervous System

Brain

Reflex: automatic response to stimuli.

REFLEX ACTION

Hand touches fire.

Sensory neurons sends signal to interneurons.

Interneurons activate motor neurons to pull

hand away.

Examples of Reflexes: - Sneezing - Blinking - Shivers - Twitching - Blushing - Yawning

Endocrine system: consists of glands that secrete chemical messengers called hormones in your blood.

Hormones are chemical messages that travel to target organs.

When they act on our brain they influence our interest in sex, food, and aggression.

THE ENDOCRINE SYSTEM

The endocrine system acts like the nervous system, but not nearly as fast. It may take several seconds for messages to be delivered.

Hormones are chemically identical to neurotransmitters.

Its effects are longer lasting and feelings are still there even after the mind has moved on.


Adrenal glands: on top of kidneys and secretes adrenaline (epinephrine) and noradrenaline (norepinephrine), which wakes up the body during stress and prepares it for action.

It increases heart rate, blood pressure, and blood sugar, giving us a surge of energy, thus a surge of adrenaline!


Hypothalamus: produces hormones that stimulate or inhibit secretion of hormones by the pituitary.

It controls the pituitary gland.


Pituitary gland: most influential gland. Regulates growth and controls the other endocrine glands.

Pituitary gland triggers sex glands to release sex hormones, which influence your brain and behavior.


Brain Pituitary Other glands

Hormones Brain

Thyroid gland: produces thyroxine, which stimulates and maintains metabolic activities.

Lack of thyroxine in children can result in mental retardation.


Pancreas: insulin and glucagon regulate blood sugar that fuels all behavioral processes.

Imbalances result in diabetes and hypoglycemia, respectively.


Ovaries and testes: gonads in females and males respectively, necessary for reproduction and development of secondary sex characteristics.


What body parts make up the central nervous system? Brain and Spinal Cord BELL RINGER.

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