Biological Perspective

Why study Biology in Psychology?  The Nervous System is vital to important parts of our body: Brain, Spinal Cord, Organs, Glands, & Muscles  Where do we see the importance? When there are damages through stroke, disease, brain trauma, spinal damage

Nervous System  What is it? – Extensive network of cells that carry information to & from all parts of the body 2 Major Parts: Central Nervous System & Peripheral Nervous System

Nervous System  Central Nervous System – brain & spinal cord Brain – interprets & stores info & sends orders to muscles, organs, & glands  made up of two cells – neurons & glial cells Spinal Cord – connects the brain & the peripheral nervous system

Nervous System  Peripheral Nervous System – transmits info to & from the central nervous system 2 Main Parts: Automatic Nervous System & Somatic Nervous System

Nervous System  Peripheral Nervous System Automatic Nervous System – regulates glands, internal organs, blood vessels, pupil dilation, digestion, & blood pressure  Parasympathetic Division – maintains body under “ordinary” conditions; saves  Sympathetic Division – prepares body to react & expand energy when under stress

Nervous System  Somatic Nervous System – carries sensory info & controls movement of skeletal muscles

Neurons  Major Parts: Dendrites – receive input Soma – cell body; maintains life of cell Axons – carry messages to other cells  bundle together in “cables” = Nerves Myelin – insulates & protects the axons that travel in the body; speed up the neural message

Neurons  Neurons contain charged particles called Ions Resting Potential – when the neuron does not fire a neural impulse – neuron is negatively charged on the inside & positively charged on the outside Acting Potential – release of the neural impulse, reversal of the electrical charge when stimulated

Neurons  Key Facts: Neurons fire in an all-or-none manner Speed & Number of Neurons firing tells us the strength of the stimulus, not the strength of the impulse created  Glial Cells – separate, support, & insulate neurons & make up 90% of brain

Neurotransmitters  Help neurons communicate with each other & with the body  What are they? Chemicals found in synaptic vesicles Synaptic vesicles release neurotransmitters in to the synapse (gap) between the cells  What do they do? Effect the next cell – stimulate or inhibit the next cell from firing

Neurotransmitters  Receptor Site – holes in the dendrite or certain cells where only certain neurotransmitters fit - - allows the correct signal to continue or end  How do they get across the synaptic gap? Action Potential reaches synaptic vesicles which then releases the neurotransmitters

Neurotransmitters  2 Effects of Neurotransmitters 1) Excitatory Synapse – stimulates the next cell to fire 2) Inhibitory Synapse – stops the next cell from firing  Acetylcholine – 1 st known neurotransmitter that stimulates muscle & helps in memory formation

Neurotransmitters & Functions  Acetylcholine – excitatory or inhibitory; involved in arousal, memory, & muscle control  Serotonin – excitatory or inhibitory; involved in mood, sleep, & appetite  GABA – inhibitory; involved in sleep & inhibits movement  Glutamate – excitatory; involved in learning, memory formation & nervous system development

Neurotransmitters & Functions  Norepinephrine – excitatory; involved in arousal & mood  Dopamine – excitatory or inhibitory; involved in control of movement & sensations of pleasure  Endorphins – inhibitory; involved in pain relief  Curare – is a poison that blocks a neurotransmitters effect

Influence of Drugs on Neurotransmitters  Agonists – mimics or enhances the effects of a neurotransmitter on the next cell; increases or decreases activity of a cell  Antagonists – blocks or reduces a cell’s response to the action of other chemicals or neurotransmitters

Reuptake  Neurotransmitters are taken place into the synaptic vesicles  How can drugs effect reuptake? block reuptake  Ex/ Cocaine & Selective Serotonin Reuptake Inhibitors  One exemption – Acetylcholine

Central Nervous System  Composed of the Brain & Spinal Cord

The Brain  3 Main Functions Take in the Information Received Make Decisions Send Commands to parts of Body

The Spinal Cord  2 Main Functions: Outer Part – transmits messages to & from the brain Inner Part – controls life saving reflexes such as the pain response  3 types of neurons – sensory neurons, interneurons, & motor neurons – 3 combine to make a simple reflex arc

Spinal Cord Neurons  Sensory (afferent) Neurons – carry messages from senses to spinal cord  Motor (efferent) Neurons – carry messages from central nervous system to muscles  Interneurons – send messages from the sensory neurons to the motor neurons

Spinal Cord Injuries  Neuroplasticity – ability by the brain to respond to a trauma or any experience by changing the function & structure of cells  Scientist have been able to implant nerves to damaged areas – then “coax” damaged nerves  The Brain has been able to adapt – neurons serve new functions when old neurons are damaged

Peripheral Nervous System Somatic Nervous System & Autonomic Nervous System

Peripheral Nervous System  Parts: made up of all the nerves & neurons in the brain & spinal cord  Main Function: 1) Allows brain & spinal cord to communicate with sensory systems 2) Allows brain & spinal cord to control the muscles & glands of body

Somatic Nervous System  Main Parts: 1) Contains sensory neurons that carry messages to Central Nervous System 2) Contains motor neurons that carry messages from the Central Nervous System to the voluntary muscles

Autonomic Nervous System  Main Parts: Sympathetic – “fight-or- flight” system – prepares the body to deal with stress (anger, fear, excitement) Parasympathetic – restores & maintains normal day-today functioning of the organs (heart beat, breathing, digestion)

Looking Inside the Brain Various Ways Used to Study the Brain

EEG - Electroencephalograph

CT Scans – Comp. Tomography

MRI Scans – Magnetic Resonance Imaging

PET Scans – Positron Emission Tomography

Functional MRI

Structures of the Brain Hindbrain Structures under the Cortex Cortex

Hindbrain (bottom of brain)  Medulla – top of spinal cord; bottom of the brain – controls life sustaining functions (heartbeat, breathing, swallowing) Nerves cross over to opposite side of body  Pons – bridge between lower parts of brain to upper – relays messages between the cerebellum & cortex Influences sleep, dreaming, arousal, & coordination of movement

Hindbrain  Reticular Formation – nerves running from the hindbrain through midbrain to cerebral cortex – controls arousal & selective attention  Cerebellum – base of the skull – controls balance & maintains muscle coordination (posture & muscle tone) Controls all involuntary, rapid, fine motor movement

Structures Under Cortex (control emotion, learning, memory, & motivation)  Thalamus – round structure in center of brain – relays information from sensory organs to cerebral cortex **Not directed with sensation of smell: Smell is directed by Olfactory Bulbs  Hypothalamus – just below & in front of thalamus – regulates body temp, thirst, hunger, sexual behavior, sleep, walking, & emotions Controls Pituitary Gland – “master gland”

Structures Under Cortex  Hippocampus – under thalamus – helps learning, memory, & ability to compare sensory information to expectations Responsible for storing memories & remembering location of objects  Amygdala – near hippocampus – influences motivation, emotional control, fear response, & memory of fear  Fornix – connects hippocampus to mamillary bodies

Cortex  Outermost part of the brain; 1/10 in. thick – consists of tightly packed neurons  Cortex wrinkles (corticalization) – WHY? Allows for greater surface area (2-3 sq. ft) Associated with Human’s greater intelligence as compared with other animals

The Cortex The Lobes of the Brain

The Cortex  Cortex is divided into two cerebral hemispheres connected by a thick band of neurons called the corpus callosum  Each hemisphere has 4 sections (lobes): Occipital, Parietal, Temporal, & Frontal

4 Lobes of the Brain

Occipital Lobes  Location: Base of the cortex, back of the brain  Function: Processes Vision  Parts: 1) Primary Visual Cortex – processes visual information from eye 2) Visual Association Cortex – helps identify & make sense of visual info

Parietal Lobes  Location: back, top of brain  Function: Processes our sense of touch, temperature, body position, and taste  Parts: 1) Somatasensory Cortex – processes info from skin & internal body receptors: “upside down person”

Temporal Lobes  Location: just behind the temples of the head  Function: responsible for understanding language/speech, & hearing  Parts: 1) Primary Auditory Cortex – involves the ability to hear

Frontal Lobes  Location: front of the brain  Function: responsible for higher mental functioning, decision making, & production of speech  Parts: 1) Motor Cortex – controls movement of voluntary muscles

Associated Areas  Function: Help people make sense of the information they receive from the lower areas of the brain; Responsible for higher forms of thought  2 Major Areas: Broca’s area & Wernicke’s area

Associated Areas  1) Broca’s Area – located in the left frontal lobe – responsible for producing fluent, understandable speech. If damaged, the person has Broca’s aphasia: halting & pronouncing incorrectly. Broca’s Aphasia – inability to understand or use written or spoken language

Associated Areas  2) Wernicke’s Area – located in left temporal lobe - responsible for the understanding of language Wernicke’s aphasia - where speech is fluent but nonsensical: wrong words are used

Associated Area  Spatial Neglect - damage to the association areas on one side of the cortex, usually the right side A person with this condition will ignore information from the opposite side of the body or the opposite visual field

Split Brain  Use Website :  Answer the questions that correspond with Split-Brain studies by using the website listed above

Differences between Males & Females  Use the website listed below to see the differences between Male Brains & Female Brains

Endocrine Glands The Chemical Connection: How Hormones interact with the nervous system & affect behavior

Endocrine System  Hormones are secreted directly into the bloodstream, influencing the activity of the muscles & organs  Pituitary Gland: “Master Gland” Found in the brain under the hypothalamus Controls the secreting of human growth hormones & influences the activity of other glands Controls the levels of salt & water in our system In women controls the onset of labor & lactation

Endocrine System  Pineal Gland – located in back of brain Secrets melatonin, a hormone that regulates our sleep-wake cycle in response to changes in light  Thyroid Gland – located inside the neck Controls metabolism by secreting thyroxin  Pancreas – located deep in abdomen Controls the level of sugar in the blood by secreting insulin & glucagon Too Little = Diabetes; Too Much = Hypoglycemia

Endocrine System  Gonads – Ovaries & Testes Secret hormones to regulate sexual growth, activity, & reproduction  Adrenal Glands – 2 glands that sit on top of each kidney; split into 2 sections Controls stress reaction through the adrenal medulla’s secretion of epinephrine & norepinephrine Adrenal Cortex secretes over 30 different hormones controlling salt intake, stress, & sexual development