Chapter Two: Biology and Psychology

Chapter Two: Biology and Psychology The Nervous System: On Being Wired Phineas (1) had a tamping rod shoot through the (2) lobe of his brain. He (3) but his (4) changed significantly. The nervous system contains the (5), (6) cord, and other parts so that we can receive information from the world and act on the world. Our brain is (7) than some other animals, such as elephants and whales, but our brains are proportionally larger. Neurons are (8) that have branches, trunks and roots. Neurons lie end to end and (9) messages from a number of sources such as light, other (10) and pressure on the skin. The nervous system also contains (11) cells that remove dead neurons and waste products from the nervous system, nourish neurons. Glial cells also (12) and (13) neurons and direct their growth. Neurons have (14), or short fibers that extend like roots from the cell body to receive incoming messages, and an (15), the trunk that extends from the cell body. Neuronal axons end in small bulb like structures named (16). Neurons carry messages in (17) direction only. Neuronal axons are wrapped tightly with a white, fatty substance called (18), that insulates the axon from the electrically charged atoms found in the fluids that surround the nervous system. Myelin is part of the maturation process and minimizes the leakage of the (19) current being carried along the axon, thus allowing the messages to be carried more (20). Neurons that transmit the sensory information from the body to the nervous system are known as (21) neurons and (22) neurons send messages back to the muscles and sensory organs. Luigi Galvani demonstrated that neural impulses are (23) in nature. A message will travel from a toe to the brain in about (24) of a second. The process by

which neural impulses travel involves (25) changes that cause an electrical charge to be transmitted along the lengths of neuronal axons. In a (26) state, of when a neuron is not being stimulated, there are negatively charged (27) ions inside the neuron so the neuron is (28), or ready for firing. The (29) (30), or the electrical potential across the neural membrane when the neuron is not stimulated, is about (31) millivolts in relation to the fluid outside the neuron. When the neuron is adequately stimulated, the cell (32) changes its (33) and allows positively charged (34) ions to enter. The entry of the sodium ions into the cell cause that portion of the neuron to become (35) with respect to the outside. The electrical impulse that conducts a neural impulse along the axon is called an (36) (37). Inside the stimulated portion of the neuron, the action potential is (38) millivolts, so the membrane voltage is about (39) to (40) millivolts. The change within the neuron enables the next portion of the neuron cell to become (41) to sodium ions. Once the cell is depolarized, the positively charged (42) ions are (43) out of the cell and the cell returns to its (44) potential. A neuron (45) when the incoming messages reach a certain strength, or (46). Each time the neuron fires, the impulse is of the (47) strength; this is known as the (48) principle. Neurons can send out (49) of messages per second. When it isn t firing, it is in a (50) period. Neurons relay their messages across junctions known as a (51) ; they consist of an axon terminal from the (52) neuron, a (53) or body from the receiving neuron and a fluid filled gap called the (54) (55). Although the neural impulse is (56), it does not jump the synaptic cleft; instead the axon terminals release (57) into the synaptic cleft. When a neural impulse reaches the axon (58), sacs called synaptic (59) release varying amounts of (60) which then influence the receiving neuron. Dozens of neurotransmitters have been identified; each has it own (61) structure and can fit into a specific (62)

(63) on the receiving cell. Unused neurotransmitters are either broken down or reabsorbed by the axon terminal in a process known as (64). Some neurotransmitters act to (65), or cause other neurons to fire; others act to (66), or keep other receiving neurons from firing. Neurotransmitters have been shown to be involved in all kinds of processes from muscle (67) to thoughts and emotions. Excesses or (68) of neurotransmitters have also been linked to psychological disorders such as (69) and schizophrenia. Some neurotransmitters of interest to psychologists include: (70), which controls muscle contractions and is normally prevalent in the part of the brain called the (71) ; (72), which has been shown to be involved in voluntary movements, (73) and memory and perception of pleasure and has been linked to schizophrenia and (74) disease; (75), produced largely in the brain (76), acts as both a neurotransmitter and a (77) and is involved in general arousal, learning, memory and eating; (78) is involved in emotional arousal and sleep and deficiencies have been linked to (79) disorders, alcoholism, (80), aggression and insomnia; (81), an (82) neurotransmitter that might calm anxiety; and endorphins, which occur naturally in the brain, may increase our sense of competence, enhance the functioning of the immune system and have been linked to the pleasurable runner s high reported by long distance runners. The nervous systems consists of the (83), the (84) cord, and the (85) linking them to sensory organs, muscles and glands. The nervous system is divided into two major divisions. The brain and spinal cord make up the (86) nervous system; while the (87) (afferent) and (88) (efferent) neurons make up the (89) nervous system. The (90) nervous system allows us to receive information from the outside world; it consists of two main divisions: (91) and (92). The (93) nervous system contains sensory (afferent) and motor (efferent) neurons and transmits messages about sights, smells, temperature, etc. to the central nervous system and also controls (94) body movements like raising a

hand. The (95) nervous system regulates the glands and muscles of internal organs, and therefore controls activities such as heartbeat, (96), digestion and dilation of the pupils. The ANS also has two branches. The (97) division helps the body expend the body s resources from stored resources during a fight or flight response to a predator. The (98) branch is active during processes that (99) the body s reserves of energy. The (100) nervous system enables us to use symbols and language, which allows us to adapt to and create new environments. The CNS consists of the (101) cord and the (102). The spinal cord is a true information superhighway; it consists of a column of (103). Spinal (104) are unlearned responses to stimuli that involve only two neurons a sensory neuron and a motor neuron. The brain and spinal cord both contain (105) matter, which is composed of short, nonmyelinated neurons, and (106) matter, which contains bundles of longer, myelinated axons. We have many (107), which are automatic, (108) responses that need not involve the brain, but often do. The Brain: Wider than the Sky From injuries, such as the one that happened to Phineas (109), we can learn a lot about brain function. While accidents are useful to study, other methods tell us even more about the brain. One experimental method is purposely (110) a specific section of the brain. Another is to (111) parts of the brain using electrical probes, as Wilder Penfield did. Researchers have also used the (112) to record the brain waves that are naturally occurring. The (113) passes (114) through the head and measures the structures that reflect the beam from various angles generating a (115) - dimensional image of the brain. The (116) forms computergenerated images of parts of the brain by tracing the amount of (117) used to see which parts of the brain are most (118) during various activities. (119) uses a powerful (120) field and (121) waves that cause parts of the brain to emit signals that are measured from various angles to see which parts of the brain are most active. (122) lets researchers observe the brain while it works.

The (123), where the spinal cord rises to meet the brain, is the (124) part of the brain and consists of three major structures: the (125), which regulates basic functions like heart rate, blood pressure and respiration; the (126), which is involved in attention, alertness and respiration; and the (127), which is involved in balance and coordination. Also beginning in the hindbrain and ascending through the midbrain into the lower portion of the forebrain is the (128) (129) system that is vital to the functions of attention, sleep and arousal. The key structures of the forebrain include: the (130), which serves as a relay station for sensory stimulation and plays a role in regulation of sleep and attention; the (131), which regulates body temperature and various aspects of motivation and emotion, including hunger, thirst, sexual behavior, caring for offspring, and aggression. The (132) system is made up of several structures, including the (133), which studies have shown is involved in aggressive behavior, vigilance and learning and memory; the (134), which has been shown to be involved in memory; and parts of the (135). Finally, the (136) is responsible for thinking and language. The surface or (137), is wrinkled with ridges and valleys that allow a great deal of surface to be packed into the brain. The valleys in the cortex are called (138), and a key one divides the cerebrum in to two halves, or (139), which are connected by the (140) (141), a bundle of some 200 million nerve fibers. Each of the cerebral hemispheres is divided into four (142) ; the (143) lobe is located in front of the central fissure, while the (144) lobe lies behind it. The (145) lobe lies on the side of the brain, below the lateral fissure; and the (146) lobe lies in the back of the brain, behind and below the parietal lobe. When you see, neurons in the (147) lobe are firing. The (148) area lies in the temporal lobe. The (149) cortex, which is just behind the central fissure in the parietal lobe, (150) messages from skin senses. Sensory and motor nerves

(151) so that the left hemisphere acts on and receives inputs from the (152) side of the body. The (153) cortex, which is in the frontal lobe, causes our body to move. The areas of the cerebral cortex that are not involved in sensation or motor activity are called (154) areas; this area in the (155) region of the brain is the brain s executive center. Association areas provide us with (156) memory and help us put parts (157). In some ways the left and right (158) of the brain are alike; however, when is comes to speech and language, the two hemispheres differ. For nearly all right-handed people and most left-handed people the (159) hemisphere controls language function. Two key language centers lie within this language hemisphere. Damage to either area results in (160), or a disruption of the ability to understand or produce language. (161) area lies in the temporal lobe and responds mainly to (162) information. (163) area is located in the frontal lobe and controls the muscles used when (164). Wernicke s aphasia is impairment in speech (165) while Broca s aphasia is impairment in speech (166). Serious reading impairment can result from problems in the (167) (168), which lies between the visual cortex and Wernicke s area. People with severe cases of (169) have split-brain operations in which the (170) (171) is severed. People who have undergone this procedure typically have (172) behavior. However, they may be able to (173) describe an unseen object such as a pencil held in the hand connected to the hemisphere that contains (174) functions, yet they (175) describe it when the object is held in the other hand. The Endocrine System: Chemicals in the Bloodstream The body contains two types of (176) : glands with or without (177), which are passageways that carry substances to specific locations. The

(178) system consists of the ductless glands that release (179) into the bloodstream. Hormones have specific (180) sites and they only act in certain locations. A (181) (182) loop lets each gland know when enough hormone has been secreted and tells the gland to stop. The (183) gland lies below the (184) and is so central to the body s functioning that it is known as the (185) gland. The pituitary gland secretes (186) hormone, which regulates the growth of muscles, bones and glands; (187), which regulates maternal behavior in lower mammals and stimulates milk production in women; (188), which inhibits production of urine when body fluid levels are low; and (189), which stimulates labor in pregnant women and is connected with maternal behavior. The (190) regulates much pituitary activity by secreting (191) hormones, or factors, such as growth hormone-releasing factor. The (192) gland secretes the hormone (193), which helps regulate the (194) cycle, and may affect the onset of (195). There could also be a connection to aging and it may be a mild (196). The (197) gland produces (198), a hormone that affects the body s metabolism. Deficiencies in this hormone is called (199) can result in obesity and sluggishness in adults, or (200) in children, characterized by stunted growth and mental retardation. Too much thyroid hormone, (201), is characterized by excitability, insomnia and weight loss. The (202) glands have an outer layer, or (203), and an inner core, or (204). The adrenal cortex is regulated by ACTH and produces (205), which help to increase resistance to (206), promote muscle development, and encourage the liver to release stored (207).

The adrenal (208) produces the epinephrine and norepinephrine. Epinephrine, or (209), is produced solely by the adrenal medulla while norepinephrine, or (210), is also produced elsewhere in the body. These hormones help the body cope with (211) and stress. The male sex hormone, (212), is responsible for prenatal sexual differentiation. During puberty it also encourages the growth of (213) and bone and the development of primary (traits involved in reproduction) and secondary (traits that differentiate males and females but are not involved in reproduction) (214) characteristics. The female sex hormones, (215) and (216), are produced in the (217). (218) fosters female reproductive capacity and secondary sex characteristics, while (219) stimulates the growth of the female reproductive organs and prepares the (220) to maintain pregnancy. Life Connections: Steroids, Behavior, and Mental Processes. Steroids increase (221) mass, heighten resistance to (222) and increase the body s (223). Synthetic versions of testosterone, known as (224) steroids, are sometimes used alongside (225) hormone to enhance athletic abilities, but they are generally outlawed in sports. Steroid use is linked to (226) damage and other health issues. Evolution and Heredity: The Nature of Nature In 1871, Darwin published The Descent of Man in which he made the case that humans, like other species, were a product of (227). According to Darwin s theory of evolution, there is a struggle for (228) as various species and individuals compete for the same territories, food, water, and light. Creatures that have (229) well to survival challenges have had their numbers increase; creatures who don t have their numbers decrease. Thus, which species prosper and which fade away is determined by (230) (231). There are small random genetic variations called (232) that lead to differences

which affect the ability to adapt to change. These better adapted individuals can then (233) and transmit their traits to future generations. (234) psychology studies ways in which (235) and (236) selection are connected with mental processes and behavior. One of the concepts of evolutionary psychology is that not only are physical traits genetically transmitted, so are some patterns of (237), such as aggression, mate selection and altruism. These behavior-patterns are termed (238), or speciesspecific, because they evolved within certain species. An (239) is a stereotyped pattern of behavior that is triggered in a (240) situation and tends to resist (241). Even instinctive behavior, however, can be modified to some degree by (242). Heredity defines one s (243), which is based on (244) structures and processes. Heredity refers to the biological (245) of (246) from generation to generation. (247) is the subfield of biology that studies heredity. (248) genetics bridges the sciences of (249) and biology and is concerned with the genetic transmission of traits that give rise to patterns of (250). The field of genetics looks at both (251) behavior patterns and individual (252) among the members of a species, while behavioral genetics focuses on the latter. Heredity is a factor in almost all aspects of human behavior, (253), and (254) processes. It is also apparently involved in many (255) disorders. (256) genetics attempts to identify specific (257) that are connected with behavior and mental processes. (258) are the basic building blocks of heredity. Some traits are controlled by a single (259) of genes while others, including complex psychological traits, are (260), or determined by (261) of genes. Genes are segments of (262), which are arranged in (263) pairs and are large complex molecules of (264). DNA takes the form of a (265) (266) and has rungs made up of (267)

with names abbreviated as A, T, C and G. The Human (268) Project is studying the sequencing of DNA. Your genetic codes provides your (269) (or nature) and this genetic code interacts with environmental influences (nurture) to produce your (270). Each of us is the result of a combination of nature and nurture.

We receive (271) chromosomes each from the sperm and the ovum. The 23 rd pair are our (272) chromosomes, which determine whether we are male (XY) or female (XX). When people do not receive all (273) chromosomes, physical and behavioral abnormalities may result. For example, (274) syndrome, occurs because of an (275) chromosome. (276) studies are ways in which psychologists compare the presence of (277) and (278) patterns in people biologically related or unrelated in order to better understand the role of genetics. The more closely people are related, the more (279) they have in common. If genes are involved in a trait or behavior, then people who are (280) related are more likely to show similar traits or behavior. In (281) studies, the presence of traits and behavior patterns are compared in monozygotic (MZ), or (282), twins and dizygotic (DZ), or (283), twins. Since MZ twins share (284) of their genes, any differences between them are the result of (285). If MZ twins show greater (286) on a trait or behavior pattern than DZ twins do, that trait or behavior probably has a (287) basis. Even when MZ twins are (288) apart and DZ twins are (289) together, we see that MZ twins have many more physical similarities than DZ twins do. In addition, MZ twins resemble one another more strongly than DZ twins in intelligence, (290), and some psychological (291). (292) studies compare children who have been separated from their parents and/or from their twin at an early age. If a child reared by adoptive parents is more (293) to his/her biological parents on a specific trait, then we have strong evidence for a (294) role in the development of that trait.