Biology of human behavior - PowerPoint Presentation

1. Biology of human behaviorMrs. L. Bijayalakshmi DeviAssociate ProfessorMKSSS BTINE

2. The human being is estimated to contain at least 150 billion nerve cells called neurons each which is connected to many others. The connections between nerve cells are called synapses.Neurons are nerve cells are the information carriers of the nervous system. Neurons come in many shapes and sizes.Brain and behavior

3. Neuron have two types of fiber. DendritesAxonThe function of the axon is to conduct nerve impulses to other neurons or to muscles and glands.Dendrite are relatively short and have many branches which receives information from other neurons. So the direction of transmission is from dendrites to axon tips.In many cases, the axon has a white, fatty covering called myelin sheath. This covering increases the speed with which the nerve impulses are send down the axon.

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5. In the nervous system a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another cell.

6. Nerve impluses are electrical events of very short duration that move along the axon.When a neuron is resting and not conducting a nerve impluse, the inside of the cell has a negative electrical chargeA stimulus which excites the cell will make the inside charge less negative.At certain level (threshold), the membrane surrounding the neuron will change its characteristicsThat lead to opening the channel briefly, allowing cation (Na) to enter the cell which is a positively charge.Nerve impluses

7. Thus the inside of the neuron become positively charge for short time a millisecond (a thousandth of a second)This rapid brief change inside positivity is the nerve impulses or spike.After a nerve impulse has occurred, the neuron is restored to its original resting charge by an outward flow of Potassium ions and is ready to fire again.

8. A narrow gap between the neurons are called synaptic cleft.It help in transmitting impulses from one neuron to anothersReleasing of chemical form as vesicle in the axon terminal bouton called neurotransmitter which either excite or inhibit the nerve impulses. Neurotramitters eg. Dopamine, adrenaline, serotonin etc.Synapses and their functions

9. Brain

10. All parts of the nervous system lying outside the brain and spinal cord.The sensory and motor neurons that connect to the CNSFunction = to carry info between organs of the body and the CNSHumans have 12 pairs of cranial nerves (sensory/motor/mixed) which control the head, face, neck, shouldersExcept VAGUS nerve – controls internal organs31 pairs of spinal nerves (mixed) which take impulses to and from the spinal cordPeripheral Nervous System (PNS)

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12. Brain

13. Just above the mid brain, extended bulb on top the brain stem is known as thalamus. It lie between two hemisphere.Forebrain: Hypothalamus and pituitary glandLying below the thalamus is a small area of the forebrain is known as hypothalamus. (content nuclie for motivated behavior)Pituatary gland: is an organ that is specialized for the selection of various substances.Forebrain: Thalamus

14. When we look at the outside of a large structure of brain is called cerebrum.Human cerebrum weight about 1400 gmCerebrum is divided into two cerebral hemispheres, one on each side of head, by a deep cleft, or fissure called the longitudinal fissure.Each hemisphere is covered by the cerebral cortex which is a sheet of neurons averaging about 2.5 mm in thickness and containing billions of neurons.Since the cerebral cortex is composed mostly of neurons and fiber, it is called gray matter.Cerebrum

15. About 2/3 of the cerebral cortex is in sulci and fissuresAn important bundle of fibers known as corpus callosum connects areas of the cortex of one hemisphere with coressponding areas in the other hemisphere.Buried in the cerebrum so that they cannot be seen from the surface are clusters of grey matter known as basal ganglia (regulation and control of movement)

16. Sensory functions areas: Some areas are largely sensory in function like primary sensory areas. It process the information received from the different sensory organ and send it to association cortex or other parts of the brain where further processing occurs.Motor function areas: largely concerned with bodily movements like on the gyrus just in front of the central sulcus. It control movement because it sends nerve fiber to the brainstem and spinal cord, which then make appropriate synaptic connections so that nerve impulses wii be sent through specific peripheral nerves to the muscles.Association areas are involves in such complex psychological function like thought, memory, imagery and production and understanding of language.

17. Some of the nuclie of the thalamus, hypothalamus, and cerebrum are interconnected to form a kind of ring or border around the lower portion of the forebrain. This group of structures is known as limbic system.It include:Olfactory bulb and its connectionThe septal nucleiThe hippocampusThe amygdalaCingulate gyrus of the cerebral cortexLimbic system:

18. It is responsible for smell. It was also called smell brainInvolves in expression of emotions of fear, and rage as well as aggressive behaviorIt has reward areas or pleasures areasAmygdala and hippocampus play role in memory formation.

19. Most of the cerebral cortex lies outside the primary sensory areas and the principal motor area. These regions in the frontal, parietal, temporal and occipital lobes are called association areas because it associates or connect between sensory input and motor outputBrain and behavior: association cortex

20. About 40% of the human cerebral cortex is in the frontal lobe.(With the exception of Brocas areas and central sulcus) the cortical region has no primary or motor function. Therefore it is considered association cortex.Since frontal areas is farthest forward in the head, this association area is called as prefrontal cortexPrefrontal cortex is interconnected with visual, auditory and somatosensory cortical areas and with parietal, temporal, thalamus etc.Frontal lobe association cortex

21. Personality and general behavior after prefrontal damage:Lack of restrainsImpulsivityImmaturity in social relationshipIndifferences to othersPromiscuityLoss of initiativeDecrease spontaneous talkingReduced emotional expressionIntellectual changes like doing step by step action in sequence, planning, memory impairment etc.

22. Pareital lobe association cortex lies behind the primary somatosensory cortex and receives inputs from visual cortex, auditory cortex, somatosensory cortex and thalamus.Major outputs go to frontal and temporal association cortex, to the thalamus and subcortical structures involves in the contrl of movement.Parietal lobe association cortex

23. Personality and general behavior after parietal lobe damageThe parietal association areas of the left and right hemisphere of the human brain differ in function.Right parietal association cortex damage:Contra lateral neglect(patient neglect the left side of space and left side of body.)Left parietal association cortex damage:Problem in reading, writing, doing simple math'sDifficulty in distinct guising left or right sideShot term memory lossBoth side damage: difficulty in recognizing common object by touch alone. It is called as agnosia.Temporary lobe association cortex (assignments)

24. Left hemisphere:Understanding languageFormulating language for communicationThinking with language symbolWernicke’s area in temporal lobe is language region (damage may lead to circumstantialities like signs)Broca’s area in lower frontal lobe is the language region (damage lead to nonfluent and ungrammer talk)Association cortex: Right and left cerebral hemisphere.

25. Right hemisphere:Recognition and memory of patterns of stimulationAnalysis of the pattern of sensory input and synthesizes of information like creative painting.

26. Mind is the faculty by which one is aware of surroundings and by which one is able to experience emotions, remember reasons and make decisions.Minds has two components:Organic componentPsychological componentThere is relationship between a human body and its unique mind.Body-mind relationship:

27. The effect of the body on mind: are referring to the effects of physical identifiable events on psychological functioning on behavior.Eg. Psychoactive drug is concern both psychology and medicine.The effects of mind on body: the mind states can influence physical functioning and behavior.Effects of stress: when you have stress, your heart beat faster, increase in blood pressure etc.Mental states and health: our behavior can affects our health: stress reactions affect on the immune systemThe impact of hormone on the immune system Interaction of mind and body in behavior

28. The body may respond to stress by producing excessive stress related hormone causing artery damage. Because of stress, it may suppress the immunity of the body.Psychosomatic disease in the body – mind relation.Body-mind and illness:

29. Our muscles with bones are responsible for the bodily movements, internal and external.The term muscle tissue refers to all the contractile tissues of the body like cardiac, skeletal muscle, smooth muscle.Integration of sensory input and motor output.Sensory systems provide the input that keeps the CNS informed of changes in the external and internal environment.Output from the CNS is then conveyed to motor system which enable us to move about, alter glandular secretions etc.Muscular control of behavior

30. Muscles: The muscles are responsible for many types of movements and behaviors which are internal as well as external. The main characteristic of muscle tissue is its ability to contract and making movements possible. There are three types of muscles in our body. They are: Skeletal muscles: As the name implies skeletal muscle attaches to the skeleton and enables body movement. It is normally under voluntary (conscious) control. Cardiac muscle: It is the muscle of heart and is responsible for pumping the blood. It is under involuntary control. The smooth muscles form the walls of hollow organs (except heart) and also found in the skin and the eyes. These are responsible for a number of functions such as movement of food through the digestive tract and emptying of the urinary bladder.

31. The major functions of the muscular system are: 1. Overall movements of the body such as walking, running, and manipulation of objects with hands, maintenance of body posture, respiration, and production of body heat. 2. Muscles also help in communication functions such as speaking, writing, typing, gestures, and facial expressions. 3. They also help in constriction of organs and vessels which help propel and mix food and water in digestive tract, propel secretions from organs and regulate blood flow through vessels.Muscle Tone: Another factor related to functioning of muscles is the muscle tone. This refers to the constant tension produced over long periods of time. Muscle tone is necessary for keeping the back and legs straight, the head held in an upright position and the abdomen from bulging. Muscle contraction is very important to enable the individual to perform long term activities like running, marathon, listening to long lecture, shooting and such other activities.

32. The most motor pathways extend from the cortex of the brain to the skeletal muscles.Direct (pyramidal) pathways: Voluntary motor impulses are propagated from the motor cortex to somatic efferent neurons that innervate/ activate skeletal muscles via the direct pathways.Indirect pathways: These involve the motor cortex, basal ganglia, thalamus, cerebellum, reticular formation and nuclei in the brain stem. The muscle control is lost when the nerve centers or fibers are injured or diseased.Motor pathways in brain

33. Glands: There are many glands in human beings situated in different parts of the body. They are of two types: (i) Duct glands and (ii) ductless or endocrine glands. 1. Duct Glands: The duct glands release their secretions through small ducts or tubes into the body cavities or on to the surface of the body. For example, salivary gland, sweat glands, lacrimal glands which produce tears, glands which secrete digestive juices, etc. These glands are activated during emotional situations. For example, sweating increases during fear or anger, tears increase during grief, saliva decreases during fear and make our mouth become dry, digestion slows down during emotions, but constant emotion leads to increased secretion of hydrochloric acid leading to peptic or duodenal ulcers.Glandular control of our behavior:

34. 2. Endocrine Glands (Ductless Glands): Endocrine glands are more important from the point of view of behaviour. Endocrine glands release their secretions called ‘hormones’ directly into blood stream. The normal secretions of these hormones promote healthy and normal personality. But over or under secretion of these hormones affect the development of body, general metabolism, mental development and emotional behaviour. Some of the important glands which are directly related to the development of personality and behaviour are: 1. Pituitary gland: This is also called the master gland, because it controls the functions of many glands. There are two lobes in this gland. The anterior lobe secretes hormones called trophic hormones which influence the secretions of other glands. For example, thyrotrophic hormone, gonadotrophic hormone, etc. The anterior lobe controls the growth of body, prolactin secretion in women, insulin secretion, metabolic activities, sexual activities, etc. The hyperactivity of this gland leads to gigantism and under activity leads to dwarfism.

35. Thyroid gland: It secretes thyroxin hormone. The normal secretion of thyroxin hormone regulates oxygen consumption and helps energy output. Hyperthyroidism causes increased nervous tension or excitement, insomnia and over activity. Hypothyroidism causes sluggishness, forgetfulness, stupidity, dullness, etc. Hypothyroidism in childhood leads to a disease called cretinism and during adulthood it leads to myxoedema. 3. Parathyroid gland: These glands are four in number. They secrete a hormone called Parathyroxin. Hyposecretion leads to excitability, muscular tremors, spasms and cramps, complete decline in secretion leads to disease called tetany. Mentally, the individual becomes highly sensitive to criticisms and unable to control emotions. Hyperactivity results in lassitude, lack of interest, physical weakness and softness of bones due to lack of calcium, and lethargy due nervous weakness.

36. 4. Adrenal glands: These glands have two parts: Medulla and Cortex. The outer part is called cortex. It produces a hormone called cortin. Under secretion of cortin leads to lethargy, fatigue, lack of interest in sexual activities, irritability, depression, poor memory, sleep disturbances, indecisiveness, etc. over secretion results in over excitability, activeness, appearance of premature sexual characteristics, etc. Excess secretion in women leads to appearance of masculine characteristics such as moustache, hard voice, rough skin and growth of hairs on the chest. Adrenal medulla secretes a hormone called Adrenaline and Noradrenalin (epinephrine and nor-epinephrine). This hormone plays a very important role during emotional experiences. Adrenaline mobilizes the person for emergencies. It causes rapid heartbeat, high blood pressure, respiration, release of more energy, increasing muscular strength and decreases the function of digestive and excretory organs. , etc.

37. 5. Sex glands: These glands secrete sex hormones. At least a few male and female traits are related to the balance existing between male and female hormones. Sex hormones are necessary for the development of interest in sex and personality traits. The sex hormones in males are called Androgens and in females they are called Estrogens and Progesterone. Under or over secretion affects the personality development. So also, early and late maturation affects personality and behaviour in various ways. In addition to these glands there are some other glands such as: the pancreas produces insulin. When the insulin quantity in blood goes very high, the sugar level comes down particularly in brain, resulting in giddiness, sweating, unconscious, lack of energy in limbs

38. Pineal gland which is very important in causing males and female characteristics. Thymus gland secretes the hormones which have a bearing on sex organs and sexual activities. In this way various glands in our body have control over our behaviour. The knowledge of these glands and their functions help nurses to understand various signs and symptoms of diseases and also the behavioural deviations associated with the activities of these glands.

39. Heredity and environment:Genetics examines how genes are passed from one generation to the next, as well as how the presence or absence of a gene can be determined via sexual reproduction. Gregor Mendel is known as the father of the field of genetics, and his work with plant hybridization (specifically pea plants) demonstrated that certain traits follow particular patterns. This is referred to as the law of Mendelian inheritance.Genetic and behavior:

40. It is passing the traits to the offspring. This is the process by which an offspring cell or organism got the characteristics of its parent cell or organism. Like intelligence, personality.Genetic diversity: it is the amount of variation seen in a particular population. The differences occur in different communities, races or ethnic groups that lead to individual differences among populations. The genes have impact on the characteristics of human beings.Heredity

41. It is the ability, i.e. capability of a biological system – individual and population – that is changing over time. The base of the genetic variability is genetic variation of different biological systems in space.There are many sources of genetic variability in a population:Homologous recombination is a significant source of variability. During meiosis in sexual organisms, two homologous chromosomes from the male and female parents cross over one another and exchange genetic material. The chromosomes then split apart and are ready to form an offspring.Genetic variability

42. Immigration, emigration, and translocation – each of these is the movement of an individual into or out of a population. When an individual comes from a previously genetically isolated population into a new one it will increase the genetic variability of the next generation if it reproducesPolyploidy – having more than two homologous chromosomes allows for even more recombination during meiosis allowing for even more genetic variability in one's offspring.Diffuse centromeres – in asexual organisms where the offspring is an exact genetic copy of the parent, there are limited sources of genetic variability. One thing that increased variability, however, is having diffused instead of localized centromeres.

43. Genetic mutations – contribute to the genetic variability within a population and can have positive, negative, or neutral effects on a fitnessFactors that decrease genetic variability:Habitat fragmentation describes a discontinuity in an organism's habitat resulting from a geological process or a human-caused event.The founder effect is an event that results in populations with low genetic diversity. The founder effect occurs when a population is founded by few individuals, resulting in poor sampling of alleles in a population. Climate change is the drastic change in annual weather patterns. These changes in weather patterns can yield negative consequences for genetic diversity. Driving species out of their fundamental niche, climate changes can lower population size and genetic variation drastically.

44. Many believes that the environment of the person effects the human’s body. Environmental flexibility gives animals the opportunity to adjust to changes during their own lifetime.Genes, via their influences on morphology and physiology, create a framework within which the environment acts to shape the behavior of an individual animal. The environment can affect morphological and physiological development; in turn behavior develops as a result of that animal’s shape and internal workings. Genes also create the scaffold for learning, memory, and cognition, remarkable mechanisms that allow animals to acquire and store information about their environment for use in shaping their behavior. Environment:

45. Behavior is influenced by ‘proximate mechanisms’ (e.g., neuroendocrine, endocrine, and physiological states) that are, in turn, influenced by behavior. Behavior affects ecological interactions (e.g., predation, competition) that, in turn, affect behavior. Evolution shapes behavior and, in turn, behavior shapes the path of evolution.Nature of behavior of an organism/Integrated responses

46. While organisms typically exhibit a broad range of responses (e.g., behavioral, physiological, or induced morphological alterations) that allow them to cope with a current environment, behavior is the one type of response that provides individuals flexibility for adjusting to the wide range of environments in which they live.

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48. An integrative view of organismal biology, ecology, and evolution that emphasizes feedback loops between behavioral and other traits, ecology, and evolution. The large box indicates interactions of behavior, expressed by an individual, with physiological, morphological, and genomic traits and the external environment. This portion of the loop includes ways that an individual can, via choice, affect the environment that shapes the expression and development of its own phenotypes. In turn, the behavior expressed by an individual has external impacts by influencing other organisms with which it lives (species interactions and community structure) and, by its effect on fitness, alters the future evolution of behavioral, and other traits.

49. since behavior influences the development and expression of other phenotypic traits, it may be more useful to view behavior as part of an integrated system with ongoing feedback loops. It can be suggest that behavior has two key characteristics that allow it to have a unique influence on the dynamics of the overall integrated system.

50. First, behavioral responses typically occur faster, and are more rapidly reversible, than are other responses to environmental change. More so than many other traits, behavior depends on past conditions as well as those currently surrounding the individual. As a result, the behavior expressed at a given moment is as much an outcome of the current conditions in the surrounding environment as it is an outcome of the current state of the individual’s physiological and morphological systems.

51. Second, because organisms often exercise choice over their social or physical environments, behavior provides a way for individuals to determine the external stimuli, which will affect the subsequent development and expression of their own morphological, physiological, and behavioral traits. Thus, behavior is typically the first response when organisms are confronted by changes in the external environment, and also, via choice of environment, a way whereby organisms can influence the environmental factors that affect the development and expression of all their traits. Behavior thus plays a key role in shaping the development and expression of integrated responses to the environment.

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