C. TRUELOVE CH 6 - BODY AND BEHAVIOR

NERVOUS SYSTEM Central Nervous System (CNS) – brain and spinal cord Peripheral Nervous System (PNS) – smaller branches of nerves that reach the other parts of the body An injury to the spinal cord could result in paralysis

NEURONS Neuron – the long, thin cells of nerve tissue along which messages travel to and from the brain All or none – If stimulated more than the minimum amount required, a neuron will fire at full strength. If not, it will not fire at all. Three parts: cell body, dendrites, and the axon

NEURONS Cell body – contains the nucleus and produces energy needed to fuel the neuron Dendrites receive impulses from other neurons and send them to the cell body. Axon – long fiber that carries impulses away from the cell body toward the dendrites of the next neuron Myelin Sheath – insulates and protects the axon; speeds the transmission of impulses Axon terminals – branch out from the axon and positioned opposite the dendrite of another neuron

NEURON

NEURON CONNECTION synapse – space between the axon terminal of one neuron and the dendrites of another neuron Axon terminal releases neurotransmitters across the synapse. The neurotransmitters either excite or inhibit the transmission to the next neuron.

VOLUNTARY AND INVOLUNTARY Somatic nervous system (SNS) – part of the peripheral nervous system that controls voluntary activities (raising your hand, turning your head, etc) Autonomic nervous system (ANS) – part of the peripheral nervous system that controls involuntary activities (ex. heartbeat, lung functioning, digestion, etc) Sympathetic – part of autonomic nervous system that prepares the body to deal with emergencies or strenuous activity (speeds up the heart and reroutes blood to needed muscles, increases blood pressure and stops digestion) Parasympathetic – conserves energy and helps body to recover from strenuous activity

THE BRAIN Three parts: hindbrain, midbrain, forebrain Hindbrain – involved in the most basic processes of life. Includes the cerebellum, medulla, and pons. Cerebellum – helps control posture, balance and voluntary movements. Medulla – controls breathing, heart rate, and a variety of reflexes Pons – functions as a bridge between the spinal cord and the brain. Also produces chemicals the body needs to sleep

THE BRAIN Midbrain – small part of the brain above the pons that integrates sensory information and relays it upward. Forebrain – covers the brain’s central core, includes the thalamus, hypothalamus, and limbic system (hypothalamus, amygdala, thalamus, and hippocampus). Cerebral cortex and cerebrum is responsible for your higher thinking processes. Gives you the ability to learn and store complex and abstract information. Site of your conscious thinking processes.

THE BRAIN Thalamus – relay station for all the information that travels to and from the cortex Hypothalamus – controls functions such as hunger, thirst, sexual behavior, and the body’s reaction to change in temperature (sweat and shiver) Amygdala – controls violent emotions like rage and fear Hippocampus – important in forming memories

ABDULLA OBLONGATA

LOBES OF THE BRAIN The brain is in two hemispheres Corpus collosum – connects the two hemispheres Occipital lobe – where the visual signals are processed (what you see is processed here) Parietal lobe – concerned with senses from all over the body Temporal lobe is concerned with hearing, memory, emotion and speaking Frontal lobe is concerned with organization, planning and creative thinking All four lobes are present in both hemispheres

LEFT/RIGHT HEMISPHERES

Left hemisphere controls movements on right side of body and the right hemisphere controls movements on left side of body. In most people… Left hemisphere: verbal (speaking, understanding language, reading, writing), mathematical (adding, subtracting, multiplying, calculus, physics), analytic (analyzing separate pieces that make up a whole) Right hemisphere: nonverbal (understanding simple sentences and words), spatial (solving spatial problems such as geometry), holistic (combining parts that make up a whole)

SPLIT BRAIN

STUDYING THE BRAIN Electroencephalograph (EEG) – recording the electrical activity of the brain Computerized axial tomography (CAT) – moving ring passes X-rays through the head. Computers read the amount of radiation absorbed and transform the information into a 3D model Positron emission tomography (PET) – slightly radioactive solution injected in the blood and shows the activity going on in the brain Magnetic resonance imaging (MRI) – studies the activity and structure of the brain with nonharmful radio frequencies

ENDOCRINE GLANDS The endocrine system and the nervous system are two communication systems for sending information to and from the brain. Endocrine system sends chemical messages, called hormones, released directly into the blood stream Pituitary Gland – acts as the master gland; directed by the hypothalamus Thyroid Gland – produces thyroxine. Too little makes people feel lazy and lethargic; too much may cause people to lose weight, sleep, and become overactive

ENDOCRINE GLANDS Adrenal glands – are activated when people are angry or frightened; releases adrenaline into the bloodstream to give a person extra energy that he or she needs to handle a difficult situation Sex glands – testes in males produce testosterone. Low levels are found in females. Ovaries in females produce estrogen and progesterone. Low levels are found in males. Testosterone prenatally determines the gender, and in adolescence, is important in the growth of muscle and bone Estrogen and progesterone regulate the menstrual cycle

HORMONES VS NEUROTRANSMITTERS Both work to affect the nervous system When a chemical is used as a neurotransmitter: released beside the cell it needs to excite. When a chemical is used as a hormone: released in the bloodstream

HEREDITY AND ENVIRONMENT Nature vs Nurture – Is behavior the result of genes or environment? Twin Studies help psychologists understand nature vs nurture Identical twins – develop from a single fertilized egg (exact same genes) Fraternal twins – develop from two fertilized eggs (no more similar than any other two siblings)