Module 4 Incredible Nervous System. GENES & EVOLUTION Genetic information –Brain/body develop according to complex chemical instructions written in a

Module 4

Incredible Nervous System

GENES & EVOLUTION

• Genetic information– Brain/body develop according to complex chemical

instructions written in a human cell no larger than a grain of sand

GENES & EVOLUTION (CONT’D)

• Fertilization

– Human life has its beginnings when the father’s sperm, which contains ________________, penetrates the mother’s egg, which contains 23 chromosomes



• Zygote

– The largest human cell, about the size ________________

– A zygote is a cell that results when an egg is fertilized

– A zygote contains ________________ arranged in 23 pairs


• Chromosomes

– A short, rod-like, microscopic structure that contains a tightly coiled strand of the chemical DNA, which is an abbreviation for deoxyribonucleic acid



• Chemical alphabet

– Each chromosome contains a long, coiled strand of DNA, which resembles a ladder that has been twisted over and over upon itself

– Each rung of the DNA ladder is made up of four chemicals

– The order in which the four different chemicals combine to form rungs creates a microscopic alphabet



• Genes and proteins

– Gene • ________________________________________

________________________________________

– Proteins• ________________________________________

________________________________________________________________________________

GENES & EVOLUTION (CONT’D)• Polymorphic genes

– ______________________________ (e.g. eye color)– Combination of genes sibling receives from parents,

resulting in two siblings having different eye colors

• Dominant and recessive genes– Dominant gene:

______________________________________________________________________________________________________________________________

– Recessive gene: _________________________________________________________________________________________________________________________________________________________


• Genome

– The Human Genome Project

– Began in 1995 and cost over $2.7 billion

– Reached its first goal in 2003 of mapping all the human genes

– Researchers found only about 30,000 human genes instead of the estimated 100,000


• Genetic factors– Researchers are discovering how genetic factors

interact with the environment in the development of mental retardation, emotional and personality traits, mental disorders, and various cognitive abilities

• Fragile X syndrome– An inherited developmental disability due to a defect in

the X chromosome• Genetic testing

– Involves taking a blood, hair, skin, or other sample and then examining donor’s genes to look for specific diseases or disorders

EVOLUTION OF THE HUMAN BRAIN

• Evolution of the human brain– 1859, Charles Darwin published The Origin of

Species

• Theory of evolution– Different species arose from a common ancestor and

that those species that survived were best adapted to meet the demands of their environment

– Humans and chimpanzees share at least 98% of their DNA

EVOLUTION OF THE HUMAN BRAIN (CONT’D)


• Genetic mutations– ___________________________________________

___________________________________________________________________________________

• Natural selection– ___________________________________________

_______________________________________________________

– ______________________________________________________________________________________________________________________________


• Adaptations– Common features of a species that provide it with

improved function

• Evolutionary approach – Voluntary ideas, such as adaptation and natural

selection, explain human behaviors and mental processes

STUDYING THE LIVING BRAIN

• Brain scans– Techniques that can look through the thick

skull and picture the brain with astonishing clarity yet cause no damage to the extremely delicate brain cells

– Researchers are mapping a variety of cognitive functions

• attention, language, memory, motor skills• sites of emotional feelings and appetite• MRI and fMRI

STUDYING THE LIVING BRAIN (CONT’D)

• MRI• _____________________________• ___________________________________________

_________________________________________

• fMRI• functional magnetic resonance imaging• ___________________________________________

___________________________________________________________________________________



• Brain scans and cognitive neuroscience

– PET scan

– Positron emission tomography

– _______________________________________________________________________________________________________________________________


• Neuroimaging– PET and fMRI scans are used to identify and map the

living brain’s neural activity as a person performs complex behavioral and cognitive tasks, such as

• seeing• moving• thinking• speaking• empathizing• trusting• even reacting to TV violence


ORGANIZATION OF THE BRAIN

• Central nervous system (CNS)

– Made up of the ____________________________

– Bottom of brain is where spinal cord emerges

– Made up of neurons, bundles of axons, and dendrites that carry information back and forth between the brain and the body

ORGANIZATION OF THE BRAIN (CONT’D)


• Peripheral nervous system (PNS)– ___________________________________________

_________________________________________________________________________________________________________

• Subdivisions of the PNS– Somatic nervous system– Autonomic nervous system (ANS)– Sympathetic division– Parasympathetic division



• Somatic nervous system– Network of nerves that connect either to sensory

receptors or to muscles that you can move voluntarily, such as muscles in your limbs, back, neck, and chest

– Nerves contain two kinds of fibers• afferent

– _____________________________________• efferent

– _______________________________________________________________________________________________________________

ORGANIZATION OF THE BRAIN (CONT’D)• Autonomic nervous system (ANS)

– Regulates heart rate, breathing, blood pressure, digestion, hormone secretion, and other functions

– Sympathetic division• triggered by threatening or challenging physical or

psychological stimuli, increases physiological arousal and prepares the body for action

– Parasympathetic division• returns the body to a calmer, relaxed state and is

involved in digestion


• Major parts of the brain

– Forebrain

– Midbrain

– Hindbrain• pons• medulla• cerebellum



• Forebrain

– Largest part of the brain

– Has right and left sides called hemispheres

– Hemispheres are responsible for a number of functions, including learning and memory, speaking and language, emotional responses, experiencing sensations, initiating voluntary movements, planning, and making decisions

ORGANIZATION OF THE BRAIN (CONT’D)• Midbrain

– Has a reward or pleasure center, which is stimulated by ____________________________________________________________________________________

– Has areas for visual and auditory reflexes

– Contains the __________________, which arouses the forebrain so that it’s ready to process information from the senses


• Hindbrain

– Has three distinct structures• pons• medulla• cerebellum


• Pons– Functions as a bridge to interconnect messages

between the spinal cord and brain• Medulla

– Located on top of the spinal cord– Includes a group of cells that control vital reflexes,

such as respiration, heart rate, and blood pressure• Cerebellum

– Located in the very back and underneath the brain– Involved in coordinating motor movements but not in

initiating voluntary movements

CONTROL CENTERS: FOUR LOBES

• Wrinkled cortex

– A thin layer of cells that essentially covers the entire surface of the forebrain

CONTROL CENTERS: FOUR LOBES (CONT’D)


• Frontal lobe– ___________________________________________

________________________________________• Parietal lobe

– __________________________________________• Occipital lobe

– __________________________________________• Temporal lobe

– ___________________________________________



• Anencephaly

– Condition of being born _______________________

– If some brain or nervous tissue is present, it’s totally exposed and often damaged because the top of the skull is missing

– Survival is limited to days



• Frontal lobe: functions

– Located in front part of brain– Includes huge area of cortex– Many functions

• voluntary motor movements, interpreting and performing emotional behaviors, behaving normally in social situations, maintaining a healthy personality, paying attention to things in the environment, making decisions, executing plans

• executive functions


• Phineas Gage

• Frontal lobotomy– ___________________________________________

_____________________________________________________________________________________________________________________________



• Frontal lobe: functions

– Motor cortex– Narrow strip of cortex that’s located on the

back edge of the frontal lobe and extends down its side

– Involved in the ______________________________

– Right side controls left– Left side controls right


• Other functions of frontal lobe

– Much knowledge of other frontal lobe functions comes from individuals who had damage to that area

– Frontal lobes are involved in paying attention, organizing, planning, deciding, and carrying out various cognitive tasks and social-emotional behaviors

– Executive function


• Parietal lobe: function

– Location of somatosensory cortex

– Narrow strip of cortex that’s located on the front edge of the parietal lobe and extends down its side



• Other functions of parietal lobe

– Sensory integration– Spatial orientation– Language abilities– Visual and auditory attention– Memory– Numerical processing (counting)


• Temporal lobe: functions

– Primary auditory cortex

– Located on top edge of each temporal lobe, __________________________________________________________________________________________________________________________________________________________________________________________________________________




– Auditory association area

– Located directly below the primary auditory cortex

– Transforms basic sensory information, such as noises or sounds, ______________________________________________________________________________________________________________________________



– Broca’s area• located in left frontal lobe• necessary for combining sounds into words and

arranging words into meaningful sentences• damage: Broca’s aphasia

– person can’t speak in fluent sentences but can understand written and spoken words


– Wernicke’s area• located in the left temporal lobe• necessary for speaking in coherent sentences and

for understanding speech• damage: Wernicke’s aphasia

– Difficulty understanding spoken or written words and difficulty putting words into meaningful sentences

BROCA’S v. WERNICKE’S


• Occipital lobe: functions

– Vision– Primary visual cortex– Located at the very back of the occipital lobe– Receives electrical signals from receptors in the eyes

and transforms these signals into meaningless, basic visual sensations, such as lights, lines, shadows, colors, and textures



• Occipital lobe: functions

– Visual association area

– ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________


• Visual agnosia

– Individual fails to recognize some object, person, or color

– Has ability to see and even describe pieces or parts of some visual stimulus



• Neglect syndrome

– Refers to the failure of a patient to see objects or parts of the body on the side opposite the brain damage

– May dress only on one side of body

– May deny that opposite body parts are theirs


LIMBIC SYSTEM: OLD BRAIN

• Group of about half a dozen interconnected structures that make up the core of the forebrain

• Involved with regulating many motivational behaviors, such as obtaining food, drink, and sex

• Organizing emotional behaviors, such as fear, anger, and aggression; storing memories

• Structures and functions– Hypothalamus– Amygdala– Thalamus– Hippocampus

LIMBIC SYSTEM: OLD BRAIN (CONT’D)

LIMBIC SYSTEM: OLD BRAIN (CONT’D)• Hypothalamus

– Regulates many ______________ behaviors, including eating, drinking, and sexual responses; emotional behaviors, such as arousing the body when fighting or fleeing; and secretion of hormones, such as occurs at puberty

• Amygdala– Located in the tip of the temporal lobe– __________________________________________– Evaluates

______________________________________________________________________________________________________________________________


• Thalamus– __________________________________________– Involved in receiving sensory information, doing some

initial processing, and then relaying the sensory information to areas of the cortex

• Hippocampus– __________________________________________– Involved in saving many kinds of fleeting memories by

putting them into permanent storage in various parts of the brain


• Autonomic nervous system

– Sympathetic

– Parasympathetic


• Autonomic nervous system– Sympathetic

• ________________________________________________________________________________________________________________________

– Fight or flight• state of increased physiological arousal caused by

activation of the sympathetic division• helps body cope and survive threatening situations

– Physiological responses• increased heart rate, increased blood pressure, and

dilated pupils


• Autonomic nervous system– Parasympathetic

• _____________________________________• _____________________________________• ______________________________________

– Physiological responses• ________________________________________• ________________________________________• ________________________________________• ________________________________________


• Autonomic nervous system

– Homeostasis

• sympathetic and parasympathetic systems work together to keep the body’s level of arousal in balance for optimum functioning

ENDOCRINE SYSTEM

• Endocrine system

– Made up of numerous glands located throughout the body

– Glands secrete various chemicals called hormones• pituitary• pancreas• thyroid• adrenal glands• gonads

ENDOCRINE SYSTEM (CONT’D)


• Pituitary gland– Hangs below the hypothalamus– Divided into anterior and posterior

• Posterior (rear portion)– Regulates water and salt balance

• Anterior (front portion)– Regulates growth through secretion of growth

hormone– Produces hormones that control the adrenal cortex,

pancreas, thyroid, and pancreas



• Pancreas– Regulates the level of sugar in the bloodstream by

secreting insulin

• Thyroid– Located in the neck– Regulates metabolism through secretion of hormones


• Adrenal glands– Adrenal cortex (outside part)– Secretes hormones that regulate sugar and salt

balance

– Adrenal medulla (inside part)– Secretes two hormones that arouse the body to deal

with stress and emergencies– Epinephrine (adrenaline)– Norepinephrine (noradrenaline)


• Gonads

– Females• ovaries produce hormones that regulate sexual

development, ovulation, and growth of sex organs

– Males• testes produce hormones that regulate sexual

development, production of sperm, and growth of sex organs

Documents

Module 4 Incredible Nervous System. GENES & EVOLUTION Genetic information –Brain/body develop according to complex chemical instructions written in a