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 1/10,000 th 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

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 STRUCTURES 1) 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 SYSTEM 1) 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.