Biological Psychology
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Transcript of Biological Psychology
BIOLOGICAL PSYCHOLOGY
NeuronsNervous SystemEndocrine SystemThe Brain
Biological Psychology
A branch of psychology concerned with the links between biology and behavior/mental processes
We are all biopsychological systems. Systems are composed of subsystems
and then even smaller systems. Separate but interconnected
NEURONS
Neuron Nerve cell Building block of the nervous system
Found all over the body Brain Legs Eyes Anywhere there are nerves
Dendrites
The bushy extensions of a neuron that receive messages
Dendrite
s
Soma
Cell body Contains nucleus – DNA, genetics,
etc
Soma
Axon
The extension of a neuron through which electrical messages pass
AXON
Myelin Sheath
Layer of fatty tissue on the axon that… Protects axon Speeds neural impulse (the message)
Myelin
Sheath
Multiple sclerosis – a disease in which the
myelin sheath degenerates resulting in a
slowing of all communication to
muscles and the eventual loss of muscle control
DENDRITES LISTEN…
… AXONS SPEAK
Axon Terminals
Branches at the end of an axon that send messages to the dendrites of another neuron. End in axon terminal buttons
Axon
Term
inal
s
Axon TerminalButtons
Synapse
The junction between neurons. Synaptic gap, synaptic cleft, etc Less than a millionth of an inch wide
Synapse
Action Potential A neural impulse in the form of a brief
electrical charge that travels down the axon A neuron fires an impulse when it receives a
signal from sense receptors or by the neurotransmitters from another neuron.
Direction of ACTION POTENTIAL
Threshold
The level of stimulation required to trigger a neural impulse. All-or-nothing
It either fires…… or it
doesn’t.
I need 5 volunteers…
Stand next to each other facing the class.
Hold hands. The person farthest to the RIGHT wants
to send a message to the person farthest to the LEFT (without actually talking)– how will we do this?
When you feel the squeeze of your right hand, squeeze the right hand of the person beside you.
Right hand and arm DENDRITES
Chest SOMA
Left arm AXON
Left hand AXON TERMINALS
Neurotransmitters Chemical messengers that travel across
the synaptic gap between neurons How neurons talk to each other
1. Action potential reaches the axon’s terminal buttons.
2. Buttons release neurotransmitters (chemicals)
3. Travel across the synapse4. Bind/connect to receptor sites on the
next neuron’s dendrites
Neurotransmitters Lock-and-key relationship between
the neurotransmitter and the receptor site. When the neuron receives
neurotransmitters, it will fire/not fire
Neurotransmitters Many types of neurotransmitters that
affect us differently and are found in different parts of the brain
Neurotransmitter
Function Examples of Malfunction
Acetylcholine (ACh)
Enables muscle action, learning, and memory.
Alzheimer’s disease – ACh producing neurons deteriorate.
Dopamine Influences movement, learning, attention, and emotion (reward/pleasure)
Excess dopamine receptor activity is linked to schizophrenia.Too little dopamine in the brain can lead to Parkinson’s disease (tremors and decreased mobility).
Serotonin Affects mood, hunger, sleep, and arousal
Too little serotonin is linked to depression. (Anti-depression drugs raise serotonin levels)
Norepinephrine Helps control alertness and arousal
Too little can depress mood
DopamineSerotonin
Endorphins Natural, opiate-like
neurotransmitters linked to pain control and pleasure
Inhibit (block) pain Ex: Runner’s high One of the top
suggested remedies for depression is exercise naturally produce chemicals that will stimulate pleasure and happiness
INTERACTIVE NEURON
“Happy people don’t kill their husbands!”
IMPORTANT
Communication WITHIN a neuron… ELECTRICAL – action potential
Communication BETWEEN neurons… CHEMICAL - neurotransmitters
NERVOUS SYSTEM
Nervous System
The body’s speedy electrochemical communication network consisting of all nerve cells Building blocks are neurons
2 parts Peripheral Nervous System (PNS) Central Nervous System (CNS)
Nervous System
PNS CNS
Central Nervous System (CNS) The brain and the spinal cord
Peripheral Nervous System (PNS) the sensory and motor neurons that
connect the CNS to the rest of the body. Everything but the brain and spinal cord
Nerves
In the PNS Neural cables Connect the CNS
to muscles, glands, and sense organs Ex: optic nerve
connects the eye to the brain (sense organ – PNS to the brain – CNS)
Nervous System Neurons
Information travels through the nervous system in 3 type of neurons.
1. Sensory neurons – carry incoming information from the senses to the CNS
2. Interneurons – CNS neurons that internally communicate between sensory inputs and motor outputs
3. Motor Neurons – carry out going information from the CNS to muscles and glands
Sensory feel… Inter interpret… Motor move
What happens if the Spinal Cord is severed? Paralysis because
sensory messages cannot reach brain and motor messages cannot leave brain
Paraplegia - patient can still move two limbs
Quadriplegia - all four limbs are paralyzed
Most famous case in recent times was the actor Christopher Reeves ( d. 2004)
Somatic and Autonomic Nervous Systems
Somatic – controls the body’s skeletal muscles Running, dancing, etc
Autonomic – controls the glands and the muscles of internal organs Heartbeat, digestion, sweating
PNS
Autonomic Somatic
Somatic – Skeletal
Autonomic - Automatic
Sympathetic and Parasympathetic Nervous Systems Sympathetic –
arouses the body Parasympathetic –
calms the body Parasympathetic -
paralyzing
Autonomic
Sympathetic Parasympathetic
Let’s Put It All Together! Nervous
System
Peripheral(PNS)
SomaticAutonomic
ParasympatheticSympathetic
Central(CNS)
THE ENDOCRINE SYSTEM
Endocrine System
The body’s “slow” chemical communication system made of glands that secrete hormones into the bloodstream
Hormones – chemical messengers manufactured by glands Travel slowly in the bloodstream When hormones act on the brain, they can trigger
interest in sex, food, aggression, “flight or fight”
Gland - An organ in the body that secretes a substance for use somewhere else in the body
Hormones vs NeurotransmittersHormones Neurotransmitters
chemical messengers for the endocrine system
Travel in the blood stream
Chemical messengers in the brain
Travel in the brain in the synapse between neurons
The endocrine system tries to keep a balance in the body while we respond to feelings of stress, anger, fear, and
exertion.
Adrenal Gland
Pair of glands above the kidneys that release adrenaline and noradrenalin which helps to arouse the body in times of stress Increase heart rate, blood
pressure, and blood sugar for energy
Hormones can last in the bloodstream after the triggering event.
Daughter Lifts Car Off Dad
Pituitary Gland
Small pea-shaped gland in the limbic system of the brain Most influential gland –
“master” gland Regulates growth
(growth hormone) and controls other glands
Controlled by the hypothalamus
Gigantism – caused by a tumor on the
pituitary gland
THE BRAIN
The Brain Brain size ≠ Intelligence Brain structure and complexity =
Intelligence
Brainstem Begins where the
spinal cord enters the brain, responsible for basic survival functions severe brainstem
injuries = death
Brainstem = area in the red box
Medulla
At the base of the brain stem Controls heartbeat and breathing
Pons
Above the medulla Helps coordinate movement by relaying
information to the cerebellum
Thalamus
On top of the brainstem The brains sensory switchboard, directs
sensory input to the correct areas in the brain
Reticular Formation A nerve network in the brainstem Helps control arousal and sleep
When stimulated, it arouses your focus. If severed, you could enter a coma. Narcolepsy = malfunction of reticular
formation
Cerebellum
Attached at the rear of the brainstem “little brain” Processes sensory input and coordinates
movement and balance
Limbic System
In the core of the brain above the brainstem
Associated with emotion and smell
Hippocampus
In the temporal lobe Processes/stores memories
Amygdala
Bean sized structures above the hippocampus Helps in the storage of emotional
events/memories Influences fear and aggression
Hypothalamus Below the thalamus
Directs maintenance activities (eating, drinking, body temp.)
Controls the pituitary gland Interprets emotions
and tells the pituitary gland which glands need to secrete hormones
Cerebral Cortex Interconnected cells that cover the
hemispheres of the brain Like bark on a tree Divided into 4 lobes - FPOT
Frontal Lobe Behind the forehead
Speaking, muscle movements, making plans/judgments, personality
Contains the motor cortex that sends outgoing movements.
Parietal Lobe
At the top of the head. Contains the sensory cortex that
receives incoming sensory information
Occipital Lobe
At the rear of the brain Contains the visual cortex that
receives and interprets information from the opposite visual field.
Temporal Lobe
On either side of the head between the ears.
Contains the auditory cortex that receives auditory input, each of which receive information from the opposite ear.
Association Areas
Areas in the cerebral cortex that are not the sensory, motor, visual, or auditory cortexes.
Broca’s area In the left hemisphere
in the frontal lobe Controls language
expression and speech
Wernicke’s area In the left
hemisphere in the temporal lobe
Controls language reception and comprehension
Split Brain When the two brain
hemispheres are not attached by the corpus callosum
Corpus callosum Band of neural fibers
that connects the two brain hemispheres together and allows them to communicate
Possible to survive with a split brain, but may have difficultly integrating vision, speech, and motor skills.
Studying the Brain Lesion – damage to brain tissue
Allows us to study the functions of the brain in circumstances that would be unethical to replicate
Ex: Phineas Gage Gabrielle Giffords’ brain after attempted
assassination still has difficulty speaking and walking, and her
right arm is paralyzed. She continues to undergo speech and physical therapy.
Electroencephalogram (EEG) An amplified recording of the waves
of electrical activity that sweep across the brain’s surface; measured by electrodes placed on the scalp
Positron emission tomography (PET) Scan A visual display of brain activity that
detects where a radioactive form of glucose goes while the brain performs a given task.
Magnetic Resonance Imaging (MRI)
A technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue, allowing us to see structures within the brain.
Functional MRI (fMRI) -
A technique for revealing blood flow and therefore, brain activity by comparing successive MRI scans