physiological bases of human behavior

7/29/2019 Physiological Bases of Human Behavior

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Physiological Bases of Human

Behavior


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Nervous System

Contains many cells that are busy

integrating and relaying information.

It is a living tissue composed of cells .

Two major categories:

GLIANEURONS OR NERVE

CELL


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Neuron

It is the individual cells in the nervous

system that receive, integrate and transmitinformation.

The basic unit of the nervous system is of

differing shapes, sizes and function.


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Part of Neuron

CELL BODY/SOMA contains the nucleus whichprovides nourishment and insulation.

DENDRITES receive signals from the

neighboring neurons and carry them back to thecell body.

AXONS relatively longer than the other neuronswhich carries messages to the other neuron.

Axons terminate in small bulges calledTerminal Buttons that send messages toother neurons


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Myelin Sheath

These are fatty tissue and proteinssurrounding the axons.

Gray is the color of the cell bodies and white is

the color of myelin sheath.

Speed of condition is matched by thethickness of the myelin sheath.


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Kinds of Neuron According to

Basic Function

1. Sensory(Afferent neurons) conveys

information from the bodys sense organs to

the brain and spinal cord. This is initiated by

the receptor specialize cells in the sense

organs, muscles, skin and joints that detect

physical or chemical change and convert

these into impulse that pass along thesensory neurons.


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2. Motor (Efferent neurons) carry impulse

away from the brain and spiral cord to the

reacting organs, the muscles and glands.

3. Association/Inter-neurons connect the

neurons together and combine the activities

of the sensory and motor neurons.

Glial Cells (Greek word glia means glue) these are the

non-neural celss that surround the neurons

and ensure that it can perform its function

while holding them in place.


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Neurotransmitters

This neural impulse reaches an axons terminalbuttons, it triggers the release of chemicalmessengers.

The molecules diffuse across the synaptic cleftand binds through receptor sites on thepostsynaptic neurons.

It can bind only to receptor sites that itsmolecular structure will fit into, much like akey must fit the lock (Weiten, 2008)


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How The Neurons Fire

ALL-or-NONE-LAW

The firing neurons occurs at either in fullstrength or not at all. After each firing, theneuron needs time to recover which is called therefractory period.

RESTING STATE

The state of the neuron when not firing aneural impulse and when the message arrives,gate in the cell membrane open briefly to allowpositivele charged ions to rush in rates as high as100million ions per second(Feldman, 2010).


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ACTION POTENTIAL

The time when there is a release of the neural impulseconsisting of a reversal of the electrical charge within the

axon.THE SYNAPSE: SENDING THE MESSAGE TOOTHER CELL

Two neurons do not actually meet. They separated bythe synaptic cleft which is a microscopic gap between the

terminal button of one neuron and the cell membrane ofanother neuron.

This situation, the neurons that send a signal acrossthe gap is called pre-synaptic neuron and the neurons thatreceive the signals is called post-synaptic neuron.

NEURONTRANSMITTER: MESSENGER OF THENETWORK

These are chemicals that carry message acrossthe synapse or cell body of a receiving neuron.


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ORGANIZATION OF THE NERVOUS

SYSTEM

A. Central Nervous System (CNS): Brain-Spinal Cord

BRAIN Protection: Skull SPINAL CORD

Protection: Vertebrae

B. Peripheral Nervous System(PNS): Extension of CNS

Somatic System

Reacts to outsides stimuli

Autonomic System

Maintains homeostasis

Sympathetic System

Response: Involuntary

Parasympathetic System

Response: Normal


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Modern Brain Scanning Techniques: Providing

Snapshots of its Internal Works

1. Electroencephalogram (EEG) records electrical activity in thebrain electrodes placed on the outside of the skull. The deviceused to assess brain damage, epilepsy and other problems.

2. Positron Emmission Tomography (PET) scans show thebiochemical activity within the while hearing, seeing, thinking andspeaking.

3. Functional Magnetic Resonance Imaging (FMRI) scans provide adetailed, three-dimensional computer image of the brainstructures and activity by aiming a powerful magnetic field at thebody.

4. Computerized/Computed Tomography (CT) scan produces a

three-dimensional image obtained from X-rays of the head thatarea assembled into a composite image by a computer.

5. Transcranial Magnetic Stimulation (TMS) one of the newesttypes of scans. The enormous advantage of TMS, of course, is thatthe virtual cut is only temporary (Fedman, 2010; Santrock, 2005;White, 2009).


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Major Parts of the Brain

A human brain which can easily be held in one

hand, weighs about 1,350 grams or 3 pounds,

and has the consistency of a firm Jell-O.

Major Areas:

Forebrain

Midbrain

Hindbrain


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The Hindbrain

- The lowest portion of the brain.

Three Identified Structure:

Medulla it controls some sensitive body functions

such as breathing, heartbeat, blood pressure and bodyposture.

Pons joining two halves of the cerebellum, this liesadjacent to it containing large bundles of nerves.

Cerebellum extends from the rear of the hindbrain,just above the medulla and behind the pons. It consistof two-rounded structures thought to play importantroles in motor coordinator(Santock, 2005).


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The Midbrain

Relays information between the brain and theeyes and the ears.

Two Systems of the midbrain that are of

special interest:

Reticular Formation

Small groups of neurons that use the

neurotransmitter serotonin, dopamine and

norepinephrine.


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The Forebrain

The largest part of the brain, which has left

and right sides that are called hemispheres.that connected by a wide band of the fiber,

are responsible for an incredible number of

functions.


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THE CEREBRAL CORTEX: Our

New Brain

Cortex means cover

It consist of a mass of deeply folded, rippled,

convoluted tissue.

Cortex is divided into two hemispheres called

CELEBRAL HEMISHERES, which are connected

by a thick, tough band of neural fibers (axons)

called CORP CALLOSUM which literally means

hard bodies as calluses on the feet are hard.


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The cortex has four major sectionscalled LOBES

1. Frontal Lobe (personality)

2. Parietal Lobe (spatial location)

3. Temporal Lobe (languages processing)

4. Occipital Lobe (vision)


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Three main areas in the Cerebral

Cortex:

Motor Areas largely reponsible for the

voluntary movement.

Association Areas responsible for the

coordination and interpretation of

information.

Sensory Areas include three regions


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THE LIMBIC SYSTEM: Old Brain

Its structure are found in the inner margin of

the upper brain which includes the thalamus,hypothalamus, and amygdale. In general, the

limbic system is involved in emotion,

motivation and learning.


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Thalamus (inner chamber)

- the middle of the central core that acts primarily to

relay information about senses.Hypothalamus (below the inner chamber)

- regulates body temperature, thirst, hunger, sleepingand waking, sexual activity and emotions.

Hippocampus (Greek word for sea horse)- located inside the temporal lobe which isresponsible for the formation of long-termmemories and the storage of memory for the

location of objects.Amygdala (almond)

- area of the brain located near the hippocampus.


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THE CHEMICAL CONNECTION: THE

ENDOCRINE GLANDS

ENDORINE SYSTEM is a chemical

communication network that sends message

throughout the body via the bloodstream.

Glands are organs in the body that secrete

chemicals

Endocrine Glands have no ducts and secrete

their chemicals directly into the bloodstream.


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A. Pituitary Gland: The master of the Hormonal

Universe

Pituitary gland is located in the brain itself, just below

the hypothalamus.

Anterior Pituitary Posterior Pituitary

B. Pineal Gland It is also located in the brain near the back. It secretes

hormones called MELATONIN, which regulates the sleep-wake

cycle.


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C. Thyroid Gland

Also located inside the neck and secretes a hormone

called THYROXIN that regulates metabolism.

D. Pancreas

Controls the level of blood sugar in the body by

secreting INSULIN and GLUCAGONS.

E. Gonads

are sex glands, including the ovaries in the female and

testes in the male. They secrete hormones that

regulates sexual behavior and reproduction.


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F. Adrenal Glands

Adrenal means to or on the kidney

Each adrenal gland is divided into two sections, the

ADRENAL MEDULLA and the ADRENAL CORTEX.

CORTICOIDS

CORTISOL

physiological bases of human behavior

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