Unit III, Modules 9-13 Test

Review

• See also the Unit III notes and pages 76-122

• About 45 m.c., plus two essays; one on brain

functioning, the other review concepts from

previous units.

• Some practice questions are embedded in this

presentation

• Other practice questions are available at the

textbook website and in the textbook after each

module.

Neuron

Order of a transmission: dendrite, cell body, axon, synapse (see arrow below)

Neural Communication

Neurons, 80

Neural Communication

• (a)Dendrite

– the bushy, branching extensions of a neuron that receive messages and conduct impulses toward the (b)cell body

• (c)Axon

– the extension of a neuron, ending in branching terminal fibers, through which messages are sent to other neurons or to muscles or glands

• Myelin [MY-uh-lin] Sheath

– a layer of fatty cells segmentally encasing the fibers of many neurons

– makes possible vastly greater transmission speed of neutral impulses,

– Damage to can lead to Multiple sclerosis

Neural Communication

• Action Potential

– a neural impulse; a brief electrical charge that

travels down an axon; DEPOLARIZED

– generated by the movement of positively charges

atoms in and out of channels in the axon’s

membrane

• Threshold

– the level of stimulation required to trigger a neural

impulse

Action Potential A neural impulse. A brief electrical charge that travels down an axon and is generated by the movement of positively charged atoms in and out of channels in the axon’s membrane.

Practice question

• Multiple sclerosis is a disease that is most

directly associated with the degeneration of:

a. the myelin sheath.

b. the pituitary gland.

c. endorphins.

d. dendrites.

Myelin Sheath

– a layer of fatty cells segmentally encasing the fibers

of many neurons

– makes possible vastly greater transmission speed of

neutral impulses,

– Damage to can lead to Multiple sclerosis

Sensory neurons

• 1. Shoulder receptors detected the squeeze

• Sensory neurons carried the info to your spinal cord

• Sensory Neurons carry incoming information from the sense receptors to the CNS.

Sensory Neuron (Bipolar)

Interneurons

• carried the information to your brain

• Interneurons in your brain interpreted the info: “Hey someone squeezed my shoulder!”

• Interneurons connect the other two neurons

Interneuron Neuron (Unipolar)

Motor neurons

• carried the command for your hand to

squeeze the shoulder of the person in front

of you.

• Motor Neurons carry outgoing information from the CNS to muscles and glands.

Motor Neuron (Multipolar)

Kinds of neurons and their location

• Interneurons

– Central Nervous System (CNS) neurons that internally communicate and intervene between the sensory inputs and motor outputs

• Motor Neurons in the peripheral nervous system

– carry outgoing information from the CNS to muscles and glands

– Skeletal Nervous System

– the division of the peripheral nervous system that controls the body’s skeletal muscles

Kinds of Neurons, 62 Sensory Neurons carry incoming information from the sense receptors to the CNS. Motor Neurons carry outgoing information from the CNS to muscles and glands. Interneurons connect the two neurons.

Sensory Neuron (Bipolar)

Interneuron Neuron (Unipolar)

Motor Neuron (Multipolar)

Refractory Period & Pumps, 56

Refractory Period: After a neuron fires an action potential it pauses for a short period to recharge itself to fire again.

Sodium-Potassium Pumps: Sodium-potassium pumps pump positive ions out from the inside of the neuron, making them ready for another action potential.

Threshold, 56

Threshold: Each neuron receives depolarizing and hyperpolarizing currents from many neurons. When the depolarizing current (positive ions) minus the hyperpolarizing current (negative ions) exceed minimum intensity (threshold) the neuron fires an action potential.

Action Potential, 55 A neural impulse. A brief

electrical charge that travels down an axon and

is generated by the movement of positively

charged atoms in and out of channels in the axon’s

membrane.

Action Potential Properties

All-or-None Response: When the depolarizing current exceeds the threshold, a neuron will fire. If the depolarizing current fails to exceed the threshold, a neuron will not fire.

Intensity of an action potential remains the same throughout the length of the axon.

Parts of a Neuron

Cell Body: Life support center of the neuron.

Dendrites: Branching extensions at the cell body. Receive messages from other neurons.

Axon: Long single extension of a neuron, covered with myelin [MY-uh-lin] sheath to insulate and speed up messages through neurons.

Terminal Branches of axon: Branched endings of an axon that transmit messages to other neurons.

Neurotransmitters: chemical messengers released into synapse

Reuptake: Prozac effects prevention of for serotonin

Neurotransmitters in the synapse are reabsorbed into the sending neurons through the process of reuptake.

This process applies the brakes on neurotransmitter action.

Antidepressant drugs and serotonin,

Antidepressant drugs like

Prozac, Zoloft, and Paxil

are Selective Serotonin

Reuptake Inhibitors

(SSRIs) that improve the

mood by elevating levels

of serotonin by

inhibiting reuptake

Can lead to neurogenesis: new brain cells.

Agonists (see 82)

Botox as an antagonist, 83

A poison (botulin) is injected into the face to

block the working of ACh and relaxing the

facial muscles. Re-injections are needed.

http://test.selfinnovations.com/sc/images/crowsBefore.gif

Curare: an antagonist

• Curare acts only at muscular synapses and NOT at the synapses of the central nervous system (curare does not cross the blood-brain barrier),

• Thus, a victim of curare poisoning may be aware of what is happening until the very end.

• The victim can feel the paralysis progressing but is quickly unable to move, call out or gesture.

• If artificial respiration is performed throughout, the victim usually recovers without ill effects.

How it affects the body

• Death from curare is caused by paralysis of the respiratory muscles.

• The alkaloid curare molecule mimics the neurotransmitter ACETYLCHOLINE by binding to its receptor at muscle synapses. ACTS AS AN ANTAGONIST.

• This prevents nerves from stimulating muscle contraction.

• Paralysis sets in gradually, because curare must compete for receptor binding sites before occupying them

Practice question

• Botox injections smooth facial wrinkles

because botulin is a(n):

a. ACh antagonist.

b. dopamine antagonist.

c. ACh agonist.

d. dopamine agonist.

Agonists and antagonists, 59

• These are NOT neurotransmitters

• Agonists mimic (act like) the action of neurotransmitters

• Example: nicotine mimics Ach

• Antagonists block the action of neurotransmitters

• Example: curare blocks Ach (leading to paralysis of muscles)

Practice question

• A drug that blocks the reuptake of a

particular neurotransmitter is called a(n):

a. opiate.

b. antagonist.

c. glutamate.

d. agonist.

Motor neurons (CNS)

• carried the command for your hand to

squeeze the shoulder of the person in front

of you.

• Motor Neurons carry outgoing information from the CNS (brain and spinal column) to muscles and glands.

Motor Neuron (Multipolar)

An Examination of the effect of

autonomic nervous system on

heart rate

• One set of nerves, the sympathetic nervous

system (SNS), is the fight or flight system,

mobilizing your body.

• Another set of nerves, the parasympathetic

nervous system (PNS) works to slow down

the body’s resources

Parasympathetic

Sympathetic

• Like a symphony:

gets you excited

Practice question

• The peripheral nervous system consists of:

a. association areas.

b. the spinal cord.

c. the reticular formation.

d. sensory and motor neurons.

Interneurons

• carried the information to your brain

• Interneurons in your brain interpreted the info: “Hey someone squeezed my shoulder!”

• Interneurons connect the other two neurons

Interneuron Neuron (Unipolar)

Reflex

• a simple, automatic, inborn response to a sensory

stimulus

Skin receptors

Muscle

Sensory neuron (incoming information)

Motor neuron (outgoing information)

Brain

Interneuron

Spinal cord

Hormonal System

• Endocrine System

– the body’s “slow”

chemical

communication

system

– a set of glands that

secrete hormones

into the bloodstream

Pituitary Gland

Is called the “master gland.” The anterior pituitary lobe releases hormones that regulate other glands. The posterior lobe regulates water and salt balance.

Adrenal Glands, 91

Adrenal glands consist of the adrenal medulla and the cortex. The medulla secretes hormones (epinephrine and norepinephrine) during stressful and emotional situations, while the adrenal cortex regulates salt and carbohydrate metabolism.

Electroencephalogram (EEG), 95

– an amplified recording of the waves of electrical activity that sweep across the brain’s surface

– these waves are measured by electrodes placed on the scalp

AJ P

hoto

/ Photo

Research

ers, Inc.

PET Scan, 68

PET (positron emission tomography) Scan is a visual display of brain activity that detects a radioactive form of glucose while the brain performs a given task.

Courtesy

of N

ation

al Bro

okhav

en N

ational L

aborato

ries

MRI Scan, 68

MRI (magnetic resonance imaging) uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of brain tissue.

Both photos from Daniel Weinberger, M.D., CBDB, NIMH

Practice question

• Which of the following would be most useful for detecting the brain areas that are most active as a person performs mathematical calculations? a. a brain lesion b. an fMRI c. a PET scan d. a hemispherectomy

Cerebral cortex

Left hemisphere

Right hemisphere

Corpus

callosum

Thalamus

Hypothalamus

Pituitary

Reticular

formation

Medulla

Spinal

cord

Cerebellum

Amygdala

Hippocampus

Cerebral cortex Limbic system Brainstem

Brain Stem, 71

The Medulla is the base of the brainstem that controls heartbeat and breathing.

Reticular Formation is a nerve network in the brainstem that plays an important role in controlling arousal and alertness.

The thalamus (Hal + Amos) 72

The brain’s sensory switchboard, located on top of the brainstem.

It directs messages to the sensory areas (visual, auditory, all except smell) in the cortex and transmits replies to the cerebellum and medulla.

Rats cross an electrified grid for self-stimulation when electrodes are placed in the reward (hypothalamus) center (top picture). When the limbic system is manipulated, a rat will navigate fields or climb up a tree (bottom picture).

Reward Center: Hypothalamus

San

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nstate

Hypothalamus (Hypo the Llamas)

– neural structure lying below (hypo) the thalamus

– directs several maintenance activities

• eating

• drinking

• body temperature

– helps govern the endocrine system via the pituitary

gland

The Limbic System: Regulation of

emotion primarily occurs in this area

Practice question

• The limbic system structure that regulates

hunger is called the:

a. thalamus.

b. amygdala.

c. hippocampus.

d. hypothalamus.

Association Areas, 79

• areas of the

cerebral cortex that

are not involved in

primary motor or

sensory functions

• involved in higher

mental functions

such as learning,

remembering,

thinking, and

speaking or

recognizing faces

Cerebral Cortex Lobes • Frontal Lobes

– involved in speaking and muscle movements and in making

plans and judgments

• Parietal Lobes

– include the sensory cortex

• Occipital Lobes

– include the visual areas, which receive visual information

from the opposite visual field

• Temporal Lobes

– include the auditory areas (hearing)

Parietal lobe, 76

• Awareness of

where your feet

and hands are

(proprioception)

Frontal lobe, 76

• Deciding your

driving destination

and how you will get

there

• Conscious control of

voluntary movement

Temporal lobe, 76

• Interpreting

auditory

information about

traffic

• Balance

(vestibular sense)

Occipital lobe, 76

• Interpreting visual

information from

the instrument

panel and traffic

Practice question

• The regions of the parietal lobes that are

involved in mathematical and spatial

reasoning are known as:

a. the angular gyrus.

b. Wernicke's areas.

c. the reticular formation.

d. association areas.

Practice question

• Brain scans indicate that well-practiced

pianists have a larger-than-usual auditory

cortex area that encodes piano sounds. This

best illustrates:

a. hemispherectomy.

b. tomography.

c. aphasia.

d. plasticity.

The “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance.

Cerebellum 98

Amygdala 99

The Amygdala consists of two almond-shaped neural clusters linked to the emotions of fear and anger.

Hippocampus

• Contributes to the

formation of memories

The cerebellum

• Cerebellum [sehr-uh-

BELL-um]

– the “little brain”

attached to the rear of

the brainstem

– it helps coordinate

voluntary movement

and balance

Motor and sensory cortex

• Motor Cortex

– area at the rear of the frontal lobes that controls

voluntary movements

• Sensory Cortex

– area at the front of the parietal lobes that registers

and processes body sensations, most critically touch

– See next slide for location and specifics

The Sensory and Motor Cortex

Phineas Gage, see page 110 • Suffered frontal lobe

damage.

• His personality changed from friendly to combative.

• More recently scientists have argued that these differences were exaggerated. He largely adjusted to this brain trauma.

Practice question

• Following massive damage to his frontal

lobes, Phineas Gage was most strikingly

debilitated by:

a. aphasia.

b. memory loss.

c. auditory hallucinations.

d. irritability.

Brain Plasticity, 110-2

• The idea that the brain, when damaged, will attempt to find news ways to reroute messages.

• Children’s brains are more plastic than adults.

Neurogenesis

= the formation of new neurons.

Splitting the Brain A procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them; used by neurosurgeons to reduce epileptic seizures.

Courtesy of Terence Williams, University of Iowa

Consciousness, 118

= our awareness of ourselves and our

environment.

Dual Processing, 120

= processing the principle that information

is often simultaneously processed on

separate conscious and unconscious

tracks.

Essays

• #1 The topic is “Super Heroes”

• #2 A review of some key terms from Chapter 18

and some material from Ch. 2