Psych 101 - 3rd Lecture- Biological Perspective

8/9/2019 Psych 101 - 3rd Lecture- Biological Perspective

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The Biological Perspective


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Nervous System -an extensive network of specialized cells that carries information to and from all parts

of the body.


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Neuroscience- a branch of the life sciences that deals with the

structure and function of neurons, nerves, andnervous tissue.

Biological Psychology or Behavioral Neuroscience- branch of neuroscience that focuses on thebiological bases of psychological processes,behavior, and learning.

Nervous System


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Neuron- the basic cell that makes upthe nervous system and that receivesand sends messages within thatsystem.

Dendrites- branchlike structures thatreceive messages from other neurons.soma the cell body of the neuronresponsible for maintaining the life of

thecell.

Axon- tubelike structure that carriesthe neural message to other cells.

STRUCTURE OF THE NEURON: THENERVOUS SYSTEMS BUILDING BLOCK Neuron


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Glial cells- cells that provide support forthe neurons to grow on and around,deliver nutrients to neurons, producemyelin to coat axons, clean up wasteproducts and dead neurons, influenceinformation processing, and, duringprenatal development, influence thegeneration of new neurons.

Myelin- fatty substances produced bycertain glial cells that coat the axons ofneurons to insulate, protect, and speedup the neural impulse.

Nerves- bundles of axons coated inmyelin that travel together through thebody.

STRUCTURE OF THE NEURON: THENERVOUS SYSTEMS BUILDING BLOCKNeuron


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diffusion - process of molecules moving from areas of high concentration to areas of

low concentration

GENERATING THE MESSAGE WITHIN THE NEURON: THE NEURAL IMPULSENeuron


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resting potential state (of the electrical potential) when the cell is resting-the state of the neuron when not firing a neural impulse

action potential- when the electrical potential is in action rather than at rest.the release of the neural impulse consisting of a reversal of the electrical charge within the

axon-each action potential sequence takes about one-thousandth of a second, so the neural

message travels very fast from 2 miles per hour in the slowest, shortest neurons to 270 miles per hour in

other neurons .

Neuron GENERATING THE MESSAGE WITHIN THE NEURON: THE NEURAL IMPULSE


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How do neurons use neurotransmitters to communicate with each other and with the body?

axon terminals - branches at the end ofthe axon

synaptic knobs- may also be called terminal buttons -rounded areas on the endof the axon

synaptic vesicles - saclike structuresfound inside the synaptic knob containingchemicals

SENDING THE MESSAGE TO OTHER CELLS: THE SYNAPSENeuron


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Neurotransmitter- chemical found in the synaptic vesicles that, whenreleased, has an effect on the next cell.

synapse (synaptic gap)- microscopic fluid-filled space between the synapticknob of one cell and the dendrites or surfaceof the next cell.

receptor sites- 3-dimensional proteins on the surface of the dendrites orcertain cells of the muscles and glands, which areshaped to fit only certain neurotransmitters

excitatory synapse- synapse at which a neurotransmitter causes thereceiving cell to fire.

inhibitory synapse- synapse at which a neurotransmitter causes the

receiving cell to stop firing.

Antagonists- chemical substances that block or reduce a cells response tothe action of other chemicals or neurotransmitters.

Agonists- chemical substances that mimic or enhance the effects of aneurotransmitter on the receptor sites of the next cell, increasing ordecreasing the activity of that cell.

MESSENGERS OF THE NETWORKNeurotransmitters


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Neural Regulators or Neural Peptides- neurotransmitters directly control the

release of other neurotransmitters.

Endorphins- pain-controlling chemicals in the body

-comes from the term e ndogenous

morphine (Endogenous means native tothe area in this case, native to thebody.)



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Reuptake- process by which neurotransmittersare taken back into the synaptic vesicles

Enzymatic Degradation- process by which structure ofneurotransmitter is altered so it can nolonger act on a Receptor

CLEANING UP THE SYNAPSE: REUPTAKE AND ENZYMESNeurotransmitters


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central nervous system (CNS)- composed of the brain and the spinal cord.

How do the brain and spinal cord interact?

BRAIN- the core of the nervous system, the part that makes sense ofthe information received from the senses, makes decisions, and sendscommands out to the muscles and the rest of the body.

SPINAL CORD- a long bundle of neurons that serves two vitalfunctions for the nervous system

inner section- composed of cell bodies of neuronsouter section composed mainly of myelinated axons and nerves

-purpose is to carry messages from the body up to thebrain and from the brain down to the body

Central Nervous System:The Central Processing Unit


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inner section - made up of cell bodies separated by glial cells- actually a primitive sort of brain - responsible for certain reflexes very fast, lifesaving reflexes

reflex arc - the connection of the afferent neurons to the interneurons tothe efferent neurons, resulting in a reflex action

To understand how the spinal cord reflexes work, it is important to knowthere are three basic types of neurons:

1. afferent (sensory) neurons - carry messages from the sensesto the spinal cord

2. efferent (motor) neurons - carry messages from the spinal cordto the muscles and glands

3. interneurons - receives information from the afferentneurons and sends commands to the

muscles through the efferent neurons-makes up the bulk of the neurons in the brain

THE REFLEX ARC: THREE TYPES OF NEURONSCentral Nervous System


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What happens if the spinal cord is damaged?

Neuroplasticity -the ability of the brain to constantly change both thestructure and function of many cells in the brain in response toexperience and even trauma

Stem Cells-special cells found in all the tissues of the body that arecapable of becoming other cell types (such as blood cells,nerve cells, and brain cells) when those cells need to bereplaced due to damage or wear and tear

-if implanted into areas that have been damaged, the newlydeveloped neurons may assume the roles that the original(now damaged) neurons can no longer perform

Central Nervous System


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How does the central nervous system communicate with the restof the body?

peripheral -refers to things that are not in the center or that areon the edges of the center.

peripheral nervous system- is made up of all the nerves and neurons that are not

contained in the brain and spinal cord- this system allows the brain and spinal cord to communicate

with the sensory systems of the eyes, ears, skin, and mouthand allows the brain and spinal cord to control the musclesand glands of the body

- can be divided into two major systems, the somatic nervoussystem and the autonomic nervous system

Peripheral Nervous System:Nerves on the Edge


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somatic nervous system - division of the PNS consisting of nerves that carryinformation from the senses to the CNS and from the CNS

to the voluntary muscles of the body

-made up of the sensory pathway , which comprises allthe nerves carrying messages from the senses to thecentral nervous system (those nerves containing afferentneurons), and the motor pathway , which is all of the

nerves carrying messages from the central nervoussystem to the voluntary, or skeletal, muscles of thebody muscles that allow people to move their bodies(those nerves composed of efferent neurons).

Peripheral Nervous SystemTHE SOMATIC NERVOUS SYSTEM


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Voluntary muscles -can move involuntarily when a reflex response occurs.

-they can be moved at will but are not limited to only that kind ofmovement.

Involuntary muscles - are all controlled by clumps of neurons located on or near the spinalcolumn-examples include: heart, stomach, intestines, glands (adrenal glandsand the pancreas)

***The neurons inside the spinal column are part of the centralnervous system, not the peripheral nervous system.

These large groups of neurons near the spinal column make up theautonomic nervous system .

Peripheral Nervous SystemTHE SOMATIC NERVOUS SYSTEM


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AUTONOMIC NERVOUS SYSTEM-controls everything else in the body organs, glands, and involuntarymuscles

2 SYSTEMS OF THE AUTONOMIC NERVOUS SYSTEM:

1. THE SYMPATHETIC DIVISION

- primarily located on the middle of the spinal column running fromnear thetop of the ribcage to the waist area-is in sympathy with ones emotions-usually called the fight -or- flight system because it allows people andanimals to deal with all kinds of stressful events-job is to get the body ready to deal with the stress

2. THE PARASYMPATHETIC DIVISION- might be called the eat-drink-and- rest system - located at the top and bottom of the spinal column, on either side ofthe sympathetic division neurons- job is to restore the body to normal functioning after a stressfulsituation ends- responsible for most of the ordinary, day-to-day bodily functioning,

such as regular heartbeat and normal breathing and digestion

Peripheral Nervous SystemTHE AUTONOMIC NERVOUS SYSTEM


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Endocrine glands- have no ducts and secrete their chemicals directly intothe bloodstream which carries them to organs in thebody, such as the heart, pancreas, and sex organs.

Hormones- chemicals secreted by the endocrine glands- affect behavior and emotions by stimulating muscles,organs, or other glands of the body; some also influencethe activity of the brain, producing excitatory orinhibitory effects

***As compared to synaptic communication, endocrinecommunication is generally slower due to the time ittakes hormones to travel to target organs and thebehaviors and responses they affect may not occur untilhours, weeks, or years later.

Endocrine SystemTHE ENDOCRINE GLANDS


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pituitary gland- located in the brain itself, just below thehypothalamus- the master gland , the one that controls orinfluences all of the other endocrine glands- secretes endorphins (chemicals that act on thenervous system to reduce sensitivity to pain)

2 parts of pituitary gland

1. Anterior lobe -regulates the activity of the thyroid, adrenals, and

reproductive glands -produces growth hormones

2. Posterior lobe releases antidiuretic hormonewhich helps control body water balance, andoxytocin which triggers contractions of the uterusthat occur during labor

Endocrine SystemPITUITARY GLAND


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pineal gland -also located in the brain, nearthe back, directly above the brain stem-plays an important role in several biologicalrhythms-secretes a hormone called melatonin , whichhelps tracks day length (and seasons)

Endocrine SystemPINEAL GLAND


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thyroid gland

-located inside the neck and secretes hormones thatregulate growth and metabolism

-plays a crucial role in body and brain development.

Thyroxin- hormone that regulates metabolism (howfast the body burns its available energy)

Endocrine SystemTHYROID GLAND


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Pancreas- controls the level of blood sugar inthe body by secreting insulin andglucagon

Diabetes - results when pancreas secretes toolittle insulin

Hypoglycemia or low blood sugar - resultswhen pancreas secretes too

much insulin

Endocrine SystemPANCREAS


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Everyone has 2 adrenal glands, one on top of each kidney.

adrenal medulla - releases epinephrine and norepinephrine,when people are under stress, and aids in sympathetic arousal

adrenal cortex - produces over 30 different hormones calledcorticoids (also called steroids) that regulate salt intake, helpinitiate* and control stress reactions, and also provides a sourceof sex hormones in addition to those provided by the gonads

Cortisol - one of the most important adrenal hormones-released when the body experiences stress, both physical andpsychological-important in the release of glucose into the bloodstream duringstress, providing energy for the brain itself, and the release offatty acids from the fat cells that provide the muscles with energy.

Endocrine SystemADRENAL GLANDS


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The Brain


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cortex

-is the outermost part of the brain, which is the part of thebrain most people picture when they think of what the brainlooks like

-made up of tightly packed neurons and actually is only about1/10of an inch thick on average

-very recognizable surface anatomy because it is full ofwrinkles

Why is the cortex so wrinkled?

***The wrinkling of the cortex allows a much larger area ofcortical cells to exist in the small space inside the skull. If thecortex were to be taken out, ironed flat, and measured, itwould be about 2 to 3 square feet.

BrainCORTEX


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The brain is divided into 3:

1. forebrain 2. midbrain 3. hindbrain

Brain


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Cerebrum- largest part of the brain -associated with higher cognitive functions

-composed of left&right hemispheres

Corpus callosum- joins the left&right hemispheres

BrainFOREBRAIN


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BrainFOREBRAIN


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Each hemisphere is divided into 4 lobes: 1. frontal lobe 2. parietal lobe 3. occipital lobe 4. temporal lobe

BrainFOREBRAIN


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Frontal Lobe- located at the front of the brain-where the higher mental functions of the brain planning, personality, memory storage, complexdecision making, language can be found-also helps in controlling emotions by means of itsconnection to the limbic system- contains the motor cortex , a band of neuronslocated at the back of each lobe, that controls themovements of the bodys voluntary muscles bysending commands out to the somatic division of the

peripheral nervous system(The motor cortex is laid out just like thesomatosensory cortex, which is right next door in theparietal lobes)

BrainFOREBRAIN: FRONTAL LOBE


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Parts of the Frontal Lobe:1. Prefrontal cortex2. Medial prefrontal cortex3. Orbitofrontal prefrontal cortex

The motor cortex in the frontal lobe controlsthe voluntary muscles of the body.

Cells at the top of the motor cortex controlmuscles at the bottom of the body.

Cells at the bottom of the motor cortex controlmuscles at the top of the body.

***The case of Phineas Gage.

BrainFOREBRAIN: FRONTAL LOBE


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BrainFOREBRAIN: PARIETAL LOBE

parietal lobe

- section of the brain located at the top andback of each cerebral hemisphere containingthe centers for touch, taste, and temperaturesensations

-contains the somatosensory cortex thatprocesses information from the skin andinternal body receptors for touch,

temperature, and body position.


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Occipital Lobe-located at the base of the cortex, toward theback of the brain-processes visual information from the eyes inthe primary visual cortex

(The visual association cortex , also in this lobe,is the part of the brain that helps identify andmake sense of the visual information from the

eyes.

BrainFOREBRAIN: OCCIPITAL LOBE


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BrainMIDBRAIN

-also called the mesencephalon -a small region of the brain that servesas a relay center for visual, auditory,and motor system information

Limbic System- often referred to as theemotional brain


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Limbic system -involved in emotions, motivation,memory, and learning

Limbic System includes the following: Thalamus Hypothalamus Amygdala Hippocampus Substantia Nigra Nucleus Accunbens Cingulate gyrus Entorhinal cortex Septal nuclei Mammilary bodies

BrainMIDBRAIN: LIMBIC SYSTEM


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thalamus-is a somewhat round structure in the center ofthe brain that acts as a kind of relay station forincoming sensory information-performs some processing of sensory informationbefore sending it on to the part of the cortex thatdeals with that kind of sensation hearing, sight,touch, or taste

NOTE:

***The sense of smell is unique in that signalsfrom the neurons in the sinus cavity go directlyinto special parts of the brain called olfactorybulbs , just under the front part of the brain.***Smell is the only sense that does not have tofirst pass through the thalamus.

BrainMIDBRAIN: LIMBIC SYSTEM: THALAMUS


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hypothalamus

-regulates body temperature, thirst,hunger, sleeping and waking, sexual activity,and emotions

-controls the pituitary, so the ultimateregulation of hormones lies with thehypothalamus

BrainMIDBRAIN: LIMBIC SYSTEM: HYPOTHALAMUS


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hippocampus

-is instrumental in forming long-term(permanent) declarative memories

-is located within the temporal lobes on eachside of the brain, and electrical stimulation ofthe temporal lobe may produce memory-likeor dreamlike experiences

-may be very close to the area of the brainwhere the memories for locations of objectsare stored as well

BrainMIDBRAIN: LIMBIC SYSTEM: HIPPOCAMPUS


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amygdala

-located near the hippocampus

-seem to be responsible for fear responses andmemory of fear (also the hippocampus)

-information from the senses goes to theamygdala before the upper part of the brain iseven involved, so that people can respond todanger very quickly, sometimes before they areconsciously aware of what is happening.

BrainMIDBRAIN: LIMBIC SYSTEM: AMYGDALA


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cingulate cortex

-found right above the corpus callosum

-plays an important role in both emotional andcognitive processing (such as selectiveattention, written word recognition, andworking memory )

-has been implicated in a variety of

psychological and mental disordersincluding attention-deficit/hyperactivitydisorder

BrainMIDBRAIN: LIMBIC SYSTEM: CINGULATE CORTEX


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-located towards the rear and lowerportion of the brain

-is responsible for controlling a number ofbody functions and process includingrespiration and heart rate

BrainHINDBRAIN


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Brain Stem- structure that connectsthe brain to the spinal cord The brain stem consists of three partsof the hindbrain: 1. medulla oblongata 2. pons 3. reticular formation

Cerebellum- located at the rear ofthe brain stem -influences motor control, balance

BrainHINDBRAIN


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medulla

-located at the top of the spinal column (itis the first swelling at the top of the spinal

cord, just at the very bottom of the brain)

-controls life-sustaining functions such asheartbeat, breathing, and swallowing

-it is where the sensory nerves coming from

the left and right sides of the bodycrossover, so that sensory information fromthe left side of the body goes to the rightside of the brain and vice versa.

BrainHINDBRAIN: BRAIN STEM: MEDULLA OBLONGATA


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BrainHINDBRAIN: BRAIN STEM: RETICULAR FORMATION

reticular formation

-is an area of neurons running through the middleof the medulla and the pons and slightly beyond

-responsible for peoples ability to generally attendto certain kinds of information in theirsurroundings

-helps keep people alert and aroused

reticular activating system part of the RF thatstimulates the upper part of the brain, keepingpeople awake and alert


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cerebellum

-controls all involuntary, rapid, fine motor

movement

-coordinates voluntary movements that have tohappen in rapid succession, such as walking,skating, dancing, playing a musical instrument,and even the movements of speech

-where learned reflexes, skills, and habitsare stored to allow them to become more or lessautomatic

BrainHINDBRAIN: BRAIN STEM: CEREBELLUM


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Association areas

-are made up of neurons in the cortex that are

devoted to making connections between thesensory information coming into the brain andstored memories, images, and knowledge

-help people make sense of the incomingsensory input

BrainASSOCIATION AREAS


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BROCAS AREA

-located in the left frontal lobe-area of the brain devoted to the production of speech-allows a person to speak smoothly and fluently

-named after the 19th

century neurologist Paul Broca, whofirst studied people with damage to this area

Brocas aphasia-damage to Brocas area that causes a person to be unable to getwords out in a smooth, connected fashion.-people with this condition may know exactly what they want tosay and understand what they hear others say, but they cannotcontrol the actual production of their own words.

*** Aphasia refers to an inability to use or understand eitherwritten or spoken language(Stuttering is a somewhat different problem in getting wordsstarted , rather than mispronouncing them or leaving them out, butmay also be related to Brocas area.)

BrainASSOCIATION AREAS: BROCAS AREA


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WERNICKES AREA

-located in the left temporal lobe

-named after the physiologist and Brocas contemporary,Carl Wernicke, who first studied problems arising fromdamage in this location

-involved in understanding the meaning of words

Wernickes aphasia-inability to speak fluently and pronounce wordscorrectly, but the words would be the wrong onesentirely

BrainASSOCIATION AREAS: WERNICKES AREA


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Psych 101 - 3rd Lecture- Biological Perspective