UNIT TWO:BIOLOGICAL BASES OF BEHAVIOR

The Biology Behind the Psychology

“Everything Psychological is ultimately Biological.”

What does this say to you?

Neurons: building blocks of the Nervous System

Demonstrations

Action Potential

Synaptic Transmission

Types of Neurons

Sensory Neurons (afferent) ~ 2 million

Sends messages from sense organs brain

Motor Neurons (efferent) ~ 2-3 million

Sends messages from brain muscles, organs, glands

Interneurons ~ Billions & Billions

Relay messages between sensory & motor neurons

Glial cells – “The forgotten cell” Glue cells which help connections, insulate, and clean up

Nervous System

Structurally and functionally divided into three divisions

CNS (Central Nervous System) located at the body region

PNS (Peripheral Nervous System) functionally peripheral

ANS (Autonomic Nervous System) functionally involuntary

Central Nervous System

Brain Spinal Chord

Fore Brain Mid Brain Hind Brain

Cerebrum

Thalamus

Hypothalamus

Frontal lobe

Parietal

Temporal

Occipital

Cerebellum

Pons Varolli

Medulla Oblongata

THE BRAIN

How does our brain produce behavior and mental processes?

1) Forebrain

The main area of the forebrain, governs emotion, learning, thinking, remembering and sense perception.

a) Cerebrum

It is the largest part of brain & Divided into left and right cerebral hemisphere .

It is associated with higher brain function such as thought and action

The cerebral cortex is divided into four sections, called "lobes“.

i) Parietal lobe located in in the central fissure from the frontal lobe.

• function: information to the skin senses (touch, temperature and pressure).

• If left hemisphere is damage may lose ability to read/ write and difficulty of knowing the parts of the body.

• If right hemisphere : difficulty of recognizing the left part of the body.

Four lobes:

ii) Frontal lobe – nearest to the face ( motor cortex) Function: controls the body movement.

iii) Occipital lobe – near the back of the head.Function: sensory area for awareness ( visual)Damage in the right hemisphere – loss of vision in the left.If in the left – loss vision ion the right.

iv) Temporal lobe - along the side of each hemisphere. Function: concern with hearingDamage in left hemisphere – inability to understand spoken words.

If in the right – can recognize speech but unable to recognize other organizations of sounds.

Contd…

b)Thalamus:

The thalamus is a large, dual lobed mass of grey matter buried under the cerebral cortex.

It is involved in sensory perception and regulation of motor functions.

The thalamus is a limbic system structure and it connects areas of the cerebral cortex .

Which are involved in sensory perception and movement with other parts of the brain and spinal cord that also have a role in sensation and movement.

As a regulator of sensory information, the thalamus also controls sleep and awake states of consciousness.

c) Hypothalamus

The hypothalamus controls the autonomic nervous system.

The autonomic nervous system is the portion of the nervous system responsible for maintaining homeostasis.

Thus, damage to the hypothalamus results in severe imbalances in the internal environment.

The hypothalamus contains the thirst center, the hunger center and the body's thermostat.

Thus, damage to the hypothalamus frequently results in water, glucose and temperature imbalances.

The hypothalamus controls the hypophysis (pituitary gland).

Note : Hypophysis refer to Pituitary gland

Contd…

The hypophysis is the most important endocrine gland in the body and is often referred to as the "master gland".

The hyopohysis is referred to as the master gland because it controls most of the other endocrine glands in the body such as the thyroid, adrenal gland, testis and ovaries.

By controlling the hypophysis the hypothalamus exerts control over most endocrine glands.

The hypothalamus is the site of emotions and the effect emotions can have on the body.

2)Midbrain

A short stem which serves the function of being a path between the fore brain and the hind brain is mid brain.

Tracts between the cerebrum and the spinal cord and functions as part of the overall impulse conduction system.

It also controls some auditory and visual responses such as regulation of the size of the pupil of the eye.

3)Hindbrain - includes

hindbrain is a developmental categorization of portions of the central nervous system in vertebrates.

It includes Medulla , Pons & Cerebellum

a) Cerebellum

located at the base of the brain just above the brain stem, where the spinal cord meets the brain

It receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates motor movements

It coordinates voluntary movements such as posture, balance, coordination, and speech, resulting in smooth, balanced muscular activity

Governs body balance, posture and muscular coordination

b)Pons Varolli

located above the medulla oblongata and below the midbrain

at roughly 2.5 centimeters long

Coordinates muscular activities on two side of body

The Pons serves as a message station between several areas of the brain

It helps relay messages from the cortex and the cerebellum

c)Medulla Oblongata

Location: Lower part of the brain stem

Function: Carries out and regulates life sustaining functions such as breathing, swallowing and heart rate

It's functions are involuntary, or done without thought

Endocrine System

The endocrine system controls the way your body functions. It produces hormones that travel to all parts of your body to maintain your tissues and organs. Here are a few of the areas governed by the endocrine system:

Reproduction

Responses to stress and injury

Growth and sexual development

Body energy levels

Internal balance of body systems

Bone and muscle strength

Your endocrine system produces, stores and releases hormones. When everything goes smoothly, your body functions properly.

Endocrine System

THANK YOU !!!