ap psychology unit #3: biological bases of behavior module #4: neural and hormonal systems
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UNIT #3: BIOLOGICAL BASES OF BEHAVIOR
MODULE #4: NEURAL AND
HORMONAL SYSTEMS
Phrenology – the theory that bumps on our skull could reveal our mental abilities and character traits.
Different parts of our brains have particular functions.
PHRENOLOGY
Neuron: a nerve cell; the basic unit of structure and function of your nervous system.
Three major functions: 1. receive information,
2. process it, and 3. transmit it to the rest of your body.
STRUCTURE AND FUNCTION OF THE NEURON
Cell body (cyton or soma): contains cytoplasm and the nucleus.
Nucleus: holds all the genetic information of the cell.
Dendrites: the branching extensions of a neuron that receives messages and sends impulses to the body.
STRUCTURE AND FUNCTION OF THE NEURON
Axon: the extension of a neuron through which messages pass to other neurons or to muscles or glands.
Axon Terminal: branching tip of the axon
Myelin Sheath: fatty tissue that insulate the axon and speeds up transmission.
STRUCTURE AND FUNCTION OF THE NEURON
Node of Ranvier: gaps between the myelin sheaths.
Schwann’s cells: cells that create myelin.
STRUCTURE AND FUNCTION OF THE NEURON
STRUCTURE AND FUNCTION OF THE NEURON
Dendrites
Axon
Myelin Sheath
Axon Terminal
Schwann’s Cells
Cell Body
Nucleus
Node of Ranvier
Excitatory signals neurons to go, while inhibitory signals them to stop.
When there are more excitatory signals than inhibitory signals, an action potential is triggered.
Action potential: a neural impulse; a brief electrical charge that travels down an axon.
STRUCTURE AND FUNCTION OF THE NEURON
Synapse: the point between an axon terminal and the next dendrite.
The gap at this junction is called a synaptic gap or cleft.
STRUCTURE AND FUNCTION OF THE NEURON
Neurotransmitters: chemical messengers that travel synaptic gap between neurons.
Extra neurotransmitters are sent back to the sending neuron in a process called reuptake.
Used by neurons to communicate with each other.
STRUCTURE AND FUNCTION OF THE NEURON
Acetylcholine (ACh): effects skeletal muscles, heart muscles, memory, and transmits messages between the brain and spinal cord.
Lack of ACh is associated with Alzheimer’s disease.
NEUROTRANSMITTERS
Alzheimer’s is a type of dementia that causes problems with memory, thinking, and behavior.
Symptoms develop slowly and gets worse over time.
A majority of people with Alzheimer’s are over 65 years old.
There is no cure, but there are treatments to slow it.
ALZHEIMER’S DISEASE
Dopamine: Affects alertness and movement.
Lack of dopamine is associated with Parkinson’s disease.
Too much is associated with schizophrenia.
NEUROTRANSMITTERS
Caused by a lack of dopamine in a region of the midbrain.
Symptoms include stiffness, tremors, shaking, changes in speech, and difficulty walking.
No known cure, but treatment can help relieve symptoms.
PARKINSON’S DISEASE
Stage 1: mild symptoms. Mild tremors or shaking.
Stage 2: Problems walking and maintaining balance. Inability to complete physical tasks.
Stage 3: Mildly severe symptoms. Inability to walk straight or to stand. Noticeable slowing of physical movement.
PARKINSON’S DISEASE
Stage 4: Severe symptoms. Unable to complete day-to-day tasks and cannot live on their own. Tremors/shakiness subsides.
Stage 5: Final stage. Disease takes over all physical movements. Patients are unable to take care of themselves.
PARKINSON’S DISEASE
Serotonin: associated with sexual activity, concentration and attention, moods, and emotions.
Lack of serotonin is associated with depression.
NEUROTRANSMITTERS
Endorphins: natural opiate, body’s painkiller.
Too little is associated with addiction withdrawal.
NEUROTRANSMITTERS
Other chemicals (drugs like heroine and morphine) can interfere with the action of neurotransmitters.
Agonists: copies a neurotransmitter and produces the effect of the neurotransmitter.
Antagonists: blocks the effect of the neurotransmitter or agonist.
NEUROTRANSMITTERS
The two major subdivisions are the central nervous system (CNS) and the peripheral nervous system (PNS).
ORGANIZATION OF YOUR NERVOUS SYSTEM
Central Nervous System (CNS): made up of the brain and spinal cord.
Spinal cord: starts at the base of your back and extends upward to the base of your skull where it joins your brains.
ORGANIZATION OF YOUR NERVOUS SYSTEM
Info travels through 3 types of neurons:Sensory neurons: sends information from body to brain and spinal cord.
Motor neurons: sends information from brain/spine to body.
Interneurons: “middle man”, communicates between sensory and motor neurons.
ORGANIZATION OF YOUR NERVOUS SYSTEM
Peripheral Nervous System (PNS): made up the somatic and autonomic nervous systems, and connects the CNS to the rest of your body.
Somatic Nervous System: Controls the body’s muscles.
Autonomic Nervous System: Controls the glands and internal organs.
ORGANIZATION OF YOUR NERVOUS SYSTEM
The Autonomic Nervous System is divided into two parts:
Sympathetic Nervous System: Responses that help your body deal with stressful events, including:
Accelerate your heart beat, raise your blood pressure, slow your digestion, raise your blood sugar, activate your sweat glands, which makes you alert.
ORGANIZATION OF YOUR NERVOUS SYSTEM
The Autonomic Nervous System is divided into two parts:
Parasympathetic Nervous System: Calms your body to conserve energy.
Comes after sympathetic system restoring digestive processes, returning pupils to normal size, restoring normal bladder contractions, slow breathing and heart rate, etc.
ORGANIZATION OF YOUR NERVOUS SYSTEM
Nervous System
Peripheral Nervous System
Central Nervous System
Spinal Cord
Autonomic Nervous System
Somatic Nervous System
Sympathetic Nervous System
Parasympathetic Nervous System
Brain
Reflex: automatic response to stimuli.
REFLEX ACTION
Hand touches fire.
Sensory neurons sends signal to interneurons.
Interneurons activate motor neurons to pull
hand away.
Examples of Reflexes: - Sneezing - Blinking - Shivers - Twitching - Blushing - Yawning
Endocrine system: consists of glands that secrete chemical messengers called hormones in your blood.
Hormones are chemical messages that travel to target organs.
When they act on our brain they influence our interest in sex, food, and aggression.
THE ENDOCRINE SYSTEM
Adrenal glands: on top of kidneys and secretes adrenaline (epinephrine) and noradrenaline (norepinephrine), which wakes up the body during stress and prepares it for action.
It increases heart rate, blood pressure, and blood sugar, giving us a surge of energy, thus a surge of adrenaline!
THE ENDOCRINE SYSTEM
THE ENDOCRINE SYSTEM
Pituitary gland: most influential gland. Regulates growth and controls the other endocrine glands.
THE ENDOCRINE SYSTEM
Brain Pituitary Other glands
Hormones Brain
Thyroid gland: produces thyroxine, which stimulates metabolism (burning of calories to supply your body with energy).
THE ENDOCRINE SYSTEM
Pancreas: regulates blood sugar.
Imbalances result in diabetes (high blood sugar) and hypoglycemia (low blood sugar).
THE ENDOCRINE SYSTEM
Diabetes (2 Types)Type 1: Juvenile diabetes. Diagnosed in children and young adults. 5% of people with diabetes has this.Body does not produce insulin. Insulin is a hormone that covert sugar and other foods into energy.Born with it.
THE ENDOCRINE SYSTEM
Diabetes (2 Types)Type 2: Hyperglycemia (high blood glucose)Most common form of diabetes.Body does not use the insulin it produces properly and it builds up in the blood.Can cause heart attack or a coma.
THE ENDOCRINE SYSTEM
Type 2 DiabetesThose at highest risk are:Over 45Obese or overweightGeneticsLow HDL cholesterol or high triglyceridesHigh blood pressureCertain racial/ethnic groups
THE ENDOCRINE SYSTEM
Hypoglycemia (Low Blood Glucose)
Often seen with diabetes.Body does not have enough sugar to use as fuel.
Symptoms include: confusion, dizziness, hunger, headache, irritability, sweating, weakness…
THE ENDOCRINE SYSTEM
Ovaries and testes: gonads in females and males respectively, necessary for reproduction and development of secondary sex characteristics.
THE ENDOCRINE SYSTEM