Physiological Bases of Behavior - Sensation and Perception

NERVOUS SYSTEM

A collection of hundreds of billions of specialized and interconnected cells through which messages are sent between the brain and the rest of the body

Main Divisions of the Nervous System

CENTRAL NERVOUS SYSTEM (CNS) and PERIPHERAL NERVOUS SYSTEM (PNS)

CENTRAL NERVOUS SYSTEM (CNS)

Consists of the brain and the spinal cord.

PERIPHERAL NERVOUS SYSTEM (PNS)

Compose all the nerve fibers that link the CNS to our skin, muscles, and glands.

NEURON

The basic structural and functional unit of the nervous system.

Parts of a Neuron

Cell Body, Dendrites, Axon

Cell Body

The central portion contains the nucleus of the cell and keeps the cell alive

Dendrites

Receive nerve impulses and carry them toward the cell body

Axon

Carry or transmit messages away from the cell body toward other neurons or to the muscles and glands.

Myelin Sheath

A layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal.

Terminal Button

forms junctions with other neurons

Glial Cells

Cells that surround and link to the neurons, protecting them, providing them with nutrients, and absorbing unused neurotransmitters.

Sensory or Afferent Neurons

Carry messages or nerve impulses from the sense organ toward the brain/CNS.

Motor or Efferent Neurons

Carry messages or nerve impulses away from the brain, like muscles and glands.

Interneurons, Connector Neurons or Association Neurons

Carry messages or nerve impulses within the brain/CNS

Irritability

Neurons can react to external stimulation

Conductivity

Ability of neurons to transmit nerve impulses up to the end of the nerve fiber.

Stimulus

Refers to anything that excites or initiates an activity

Electrical Signals

Nerve impulses or messages

Resting Potential or Polarization Stage

More negative than positive ions or charged particles inside the neuron, while it has more positive ions outside

Action Potential

Sending of a nerve impulse or “firing” of a neuron down the axon from the end of one neuron to the next neuron

Synapses

Spaces between the axon of a neuron.

All or Nothing Law

States that it is either that neuron reacts or not at all, but if it does react, it reacts with fullest strength.

Law of Dynamic Polarity

States that nerve impulses travel only in one direction from neuron to neuron

THE BRAIN

Controls and directs all activities in the nervous system

SPINAL CORD

The long, thin, tubular bundle of nerves and supporting cells that extends down from the brain. It is the central throughway of information for the body.

Forebrain

Consists of the cerebrum, thalamus, and hypothalamus

Midbrain

Responsible for linking the sensory and motor pathways between the upper and the lower parts of the nervous system.

Hindbrain

Composed of the pons, medulla oblongata and the cerebellum. It is connected to the spinal cord.

CEREBRUM

The largest division of the brain. It is divided into two hemispheres, each of which is divided into four lobes.

FRONTAL LOBE

Located behind the forehead and responsible primarily for thinking, planning, memory, and judgment.

PARIETAL LOBE

Located from the middle to the back of the skull, and responsible primarily for processing information about touch and taste. These lobes also receive input from vision, which helps us identify objects by touch and locate objects in space

OCCIPITAL LOBE

Located at the back of the skull, and processes visual information.

TEMPORAL LOBE

Located at the sides of the brain and responsible for hearing, language, and integrating vision and audition.

HIPPOCAMPUS (Sea Horse)

Which is responsible for changing short-term memories into long-term memories

AMYGDALA (Almond)

Cause aggressive behavior/primarily responsible for regulating our perceptions of, and reactions to, aggression and fear.

HYPOTHALAMUS

Seat of emotion, maintains homeostasis by regulating some involuntary activities/links the nervous system to the endocrine system via the pituitary gland and thus regulates body temperature, hunger, thirst, and sex.

THALAMUS

Relay center

RETICULAR ACTIVATING SYSTEM – RAS

Controls our sleep and arousal

THE BRAIN STEM

It is designed to control the most basic functions of life, including breathing, attention, and motor responses

MEDULLA OBLONGATA

Regulates the involuntary muscles - medulla, the area of the Brain Stem that controls heart rate and breathing.

PONS

A structure in the brain stem that is important to sleep and arousal.

CEREBELLUM

Coordination of voluntary motor activities- maintains body balance and posture

SOMATIC NERVOUS SYSTEM (SNS)

It is the division of the PNS that controls the external aspects of the body, including the skeletal muscles, skin, and sense organs.

THE AUTONOMIC NERVOUS SYSTEM (ANS)

It is the division of the PNS that governs the internal activities of the human body, including heart rate, breathing, digestion, salivation, perspiration, urination, and sexual arousal.

SYMPATHETIC DIVISION OF THE ANS

It is involved in preparing the body for behavior, particularly in stress response, by activating the organs and the glands in the endocrine system.

PARASYMPATHETIC DIVISION OF THE ANS

Tends to calm the body by slowing the heart and breathing and by allowing the body to recover from the activities that the sympathetic system causes.

ENDOCRINE SYSTEM

The chemical regulator of the body that consists of glands that secrete hormones that influence behavior.

Gland

It is made up of groups of cells that function to secrete hormones.

Hormone

A chemical that moves throughout the body to help regulate emotions and behaviors.

Pituitary Gland

It is responsible for controlling the body’s growth, but it also has many other influences that make it of primary importance to regulating behavior.

Pancreas

Which secretes hormones designed to keep the body supplied

with fuel to produce and maintain stores of energy

Pineal Gland

It secretes melatonin, a hormone that helps regulate the wake-sleep cycle

Thyroid and Parathyroid Glands

Which are responsible for determining how quickly the body uses energy and hormones, and controlling the amount of calcium in the blood and bones.

Adrenal Glands,

Which produce hormones that regulate salt and water balance in the body, and they are involved in metabolism, the immune system, and sexual development and function.

Testes

Secretes testosterone,

Ovaries

It produce eggs and secrete the female hormones

estrogen and progesterone.

The eye

The organ of vision sensitive to light waves.

WAVELENGTH

Which is the distance from one wave push to the next that determines its hue

INTENSITY

The amount of energy in light waves (determined by a wave's amplitude or height) that influences brightness.

SATURATION

The extent to which light contains only one wavelength, rather than many, determines our experiences of saturation: which refers to the purity or richness of color: the fewer the number of wavelengths mixed.

CORNEA

Light rays pass through this

PUPIL

Light rays enter the eye through this

IRIS

Adjusts the size of the pupil to regulate the amount of light entering the eye

LENS

A clear structure in which shape adjusts to permit us to focus on objects at varying distances

RETINA

The projected image is formed on this

CONES

Located in the center of the retina (FOVEA) for clear vision and color vision

RODS

Found outside the fovea and function best in low-light conditions

OPTIC NERVE

Rods and cones transmit neural information to the brain through this

Visual Acuity

The sharpness of vision, measured using a Snellen chart.

Nearsightedness or myopia

A condition where a person is capable of seeing nearby objects with greater activity than distant objects.

Farsightedness or hyperopia

A condition where a person can see distant objects with greater activity than nearby objects.

Presbyopia

A condition characterized by brittleness of the lens which usually begins at about the age of 38 to 46.

Strabismus or cross-eyed

A visual disorder in which both eyes cannot focus on the same point at the same time.

Astigmatism

A visual disorder caused by abnormal curvature of the lens, so that images are indistinct or distorted.

Color Blindness

A condition in which persons suffering from this are monochromats and sensitive to light and dark only.

Partial color blindness

This is more common in males and results in the ability to discriminate only two colors - red and green or blue and yellow.

Trichromatic Theory

Color vision is enabled by three types of cones - red (long), green (medium), and blue (short).

Opponent Process Theory

Visual receptors process colors in three antagonistic pairs: red green, blue-yellow, and black-white.

Ear

It is shaped to capture, vibrate, and transmit sound information to the brain.

Outer Ear

The ear canal funnels sound waves to the eardrum, which vibrates and transmits them to the middle and inner ears.

THE MIDDLE EAR

Home to the eardrum and three small bones - hammer, anvil, and stirrup - which vibrate to transmit sound.

THE STIRRUP

This balances pressure in the inner ear.

THE INNER EAR

The oval window sends vibrations to the cochlea, a snail-shaped bony tube with two membranes dividing it into three fluid-filled chambers.

ORGAN OF CORTI

Known as the "command post" of hearing, is connected to the basilar membrane.

Pitch

This is determined by frequency, measured in hertz (Hz).

Loudness

This correlates with the height of sound waves, with higher amplitudes resulting in louder sounds.

Conduction deafness

This results from damage to middle ear structures like the eardrum or bones that amplify sound.

Sensory-neural deafness

It typically results from inner ear damage, particularly to hair cells that do not regenerate or the auditory nerve.

Stimulation deafness

It is caused by exposure to loud sounds, such as at rock concerts or through using pneumatic drills or driving loud vehicles.

Smell sensations

This is triggered by molecules that enter the nose and dissolve in moist nasal tissues, coming in contact with receptor cells in the olfactory epithelium.

Anosmia

"smell blindness”

Taste buds

Located in papillae on the tongue, contain receptor cells for different tastes.

Ageusia

A temporary loss of taste

Thermal Taste

A phenomenon where simply warming or cooling the tongue produces a phantom taste sensation (like sweet, sour, or salty) without any actual food or chemicals present

Skin

Largest organ in our body discriminates five kinds of sensations: touch, pressure, warmth, cold, and pain.

TEMPERATURE

This suggests we have receptors for detecting warmth and coldness.

PAIN

It is a signal that something is wrong in the body.

GATE THEORY

Prevents transmission signals to the brain due to the limited amount of stimulation that can be processed by the nervous system at a time,

KINESTHESIA

Provides us with information about the location of our body parts, enabling us to perform a range of movements from simple tasks