THE BIOLOGY OF THE MIND!

NEURAL COMMUNICATION

• Our bodies neural information system is complexity built from simplicity• Neuron – nerve cells• Sensory neurons – carry messages from the body’s tissues and sensory

organs inward to the brain and spinal cord, for processing• Motor neurons – neurons that carry outgoing information from the brain

and spinal cord to the muscles and glands• Interneurons – located inside the brain and intervene between the

sensory neurons and the motor neurons

WHAT DOES A NEURON LOOK LIKE?• All neurons are essentially based off of the same cell body

• Dendrites receive information whereas the axons passes the message along – Axons speak, dendrites listen

• The Myelin Sheath insulates the axons and helps speed up their impulses

ACTION POTENTIAL

• Action potential is a neural impulse. It is a brief electric charge that travels down an axon.

HOW DO NERVE CELLS COMMUNICATE WITH OTHER NERVE CELLS?

• Neurons interweave and meet at a point in between themselves called a synapse.

• When an action potential reaches the knoblike terminals at an axon’s end, it triggers the release of chemical messengers, called neurotransmitters.

• Within 1/10,000th of a second, the neurotransmitter molecules cross the synaptic gap and bind to the receptor sites of the receiving neuron

• Reuptake then occurs in which the neuron reabsorbs the excels neurotransmitters.

NEURON VIDEO

• http://www.youtube.com/watch?feature=player_embedded&v=o9p2ou1IyC0

THE NERVOUS SYSTEM

• Nervous System: the body’s speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.• Central Nervous System: the brain and the spinal cord.

• Peripheral Nervous System: the sensory and motor neurons that connect the central nervous system to the rest of the body.

THE PERIPHERAL NERVOUS SYSTEM

• Contains two systems: somatic and autonomic.• Somatic Nervous System: enables voluntary control of our skeletal muscles (example:

turning a page in a book)

• Autonomic Nervous System: controls our glands and muscles of our internal organs, influencing such functions as glandular activity, heartbeat, and digestion.

• Within the autonomic nervous system there are two divisions which serve two important functions

• Sympathetic Nervous System: arouses the body, mobilizing its energy in stressful situations

• Parasympathetic Nervous System: conserves energy, calms you down, decreases heartbeat

THE CENTRAL NERVOUS SYSTEM

• Composed of the brain and the spinal cord, there are 40 billion neurons running through the CNS. There are about 400 trillion synapses in the human body.

• The brain’s neurons cluster into work groups called neural networks. Neurons that fire together, work together.

• The spinal cord is an information highway connecting the peripheral nervous system to the brain. The spinal cord runs the reflexes, which are simple, automatic responses to a sensory stimulus.

• Examples: knee-jerk, heat reflex, arousal

THE ENDOCRINE SYSTEM

• Endocrine System: the body’s “slow” chemical communication system; a set of glands that secrete hormones in the bloodstream.• Hormones: chemical messengers that are manufactured by the endocrine glands. –

travel through the bloodstream and affect other tissues

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

GLANDS

• Adrenal Gland: a pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress

• Pituitary Gland: the endocrine system’s most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.

• Feedback System BRAIN -> PITUITARY -> OTHER GLANDS-> HORMONES -> BRAIN

THE BRAIN

• Brain + body = mind

• The effect of hormones on experiences such as love reminds us that we would not be the same mind if we were a bodiless brain.

• If all of your organs were transplanted, you would be much the same person, unless one of these organs was your brain

LOWER LEVEL BRAIN STRUCTURES1) THE BRAINSTEM

• Begins where the spinal cord swells slightly after entering the skull. The slight swelling is the medulla, above that is the pons, and the midbrain.

• The brainstem controls breathing, digestion, heart rate, and other automatic processes, as well as connecting the brain with the spinal cord and the rest of the body.

2) THE THALAMUS

• Sensory switchboard – controls all the senses except smell and routes it to the higher brain regions that deal with seeing, hearing, tasting, and touching.

3) CEREBELLUM

• Means “little brain” - The Cerebellum helps us judge time, modulate our emotions, and discriminate sounds and textures – it also coordinates voluntary activity

THE LIMBIC SYSTEM1) THE AMYGDALA

• In the limbic system, it consists of two lima bean-sized neutral clusters

• The amygdala influences aggression and fear, processes emotional memories

2) THE HYPOTHALAMUS

• Just below the thalamus is the hypothalamus

• Influences memory function – long and short term memory – as well as monitors blood chemistry to keep the internal environment in a steady state – can also take orders from the brain to trigger hormones

3) THE CEREBRUM

• Makes up 75% of the brain by volume and 85% by weight – is divided by a large groove called the longitudinal fissure, into two distinct hemispheres which control the left and right sides of the body

4) CEREBRAL CORTEX

• Covers the cerebrum, is a sheet of neural tissue which is only 2-4 millimeters thick, which serves as the brains control and information processing center - it plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness.

• It envelops other brain organs such as the thalamus and hypothalamus and relays information

• The cerebral cortex contains six distinctive and interconnected layers, which are grooved and folded, allowing a large surface area to fit in the confines of the skull. Folds are called gyri and the grooves are called sulci.

MOTOR CORTEX VS. SENSORY CORTEX

• The motor cortex is an area at the rear of the frontal lobes that controls voluntary movements.

• The sensory cortex is an area at the front of the parietal lobes that registers and processes body touch and movement sensations.