Bio 300 Exam 1 Lecture

Question 1

Neuroscience VS
Behavioral Neuroscience

Answer 1

Neuroscience: interdisciplinary area of study involving psychology, biology, chemistry, medicine, mathematics, physics, engineering, and computer science. Interdisciplinary

Behavioral neuroscience:
Reciprocal relationship between biology and behavior. Impact behavior, emotion, cognition - example: placebo effect

Question 2

Trepanation

Answer 2

(skull surgery - hole in head)
Skulls show signs of healing.

Question 3

Mind-Body Problem?

Dualism?

Monism?

Answer 3

Mind-Body Problem- The problem of how a physical substance (the brain) can give rise to our sensations, thoughts and emotions (our mind).

Dualism - psyche and mind two separate entities → philosophical perspective - spiritual

Monism - mental activity is brain activity → mind is viewed as the product of the brain

Question 4

Phrenology

Answer 4

Phrenology: the correlation of bumps on the skull with personal traits and intellectual abilities, was misguided in most respects, but modern in its acceptance that different cognitive functions may be localized to specific areas in the brain.
Localization - different parts of brain are responsible for different uses

Franz Josef Gall (1758–1828) → brain is like a muscle that can actually grow the more you use it and this is not true about the head with the bumps - education people on localization

Question 5

Microscopic methods provide means for?

Fixed tissue is sliced by a?

Golgi stain?

Nissl stain?

Myelin stain?

Horseradish peroxidase?

Optical imaging?

Answer 5

Microscopic methods provide means for observing structure, organization, and connections of individual cells. - stronger microscopics to see smaller things

Fixed tissue is sliced by a microtome.

Golgi stain (observe single whole neurons - stain some neurons not all they don’t know why)

Nissl stain (cell body - what types of cells are what areas of brain)

Myelin stain (stains myelin sheath)

Horseradish peroxidase (axon pathway from origin to terminal - where does the cell start)

Optical imaging (using light)

Question 6

Lesion VS Ablation

Answer 6

Lesion: Naturally occurring and Deliberately produced damage either
Ablation: remove cut neural tissue during surgery

Question 7

Microdialysis - Chemical stimulation

Answer 7

Microdialysis: remove fluid from specific area to see which chemicals makeup that area of the brain

Question 8

Genetic Methods

Twin Studies?

Concordance rate?

Heritability?

Genetic screen?
Forward vs reverse genetic screens?

Answer 8

Twin Studies- Studies of twins, both identical and fraternal, reared apart and together. 100% identical genes, physical characteristics are more heritable

Concordance rate- The statistical probability that two cases will agree; usually used to predict the risk of an identical twin for developing a condition already diagnosed in his or her twin. A binary correlation so a yes or no where correlation is a spectrum.

Heritability- The amount that a trait varies in a population due to genetics. - really heritable: physiological characteristics like heart conditions and physical characteristics like hair color VS moderately heritable: intelligence VS less heritable: mood or anger

Genetic screen- Methods for correlating genotypes(actual gene) with phenotypes(expressed).
Forward(phenotype and find necessarily gene) vs. reverse genetic(gene of interest multiplied and observed on phenotype) screens

Question 9

Animal Subjects Guidelines
The “3 Rs” of animal research:

Answer 9

Reduce, Replace, Refine

Question 10

Types of Muscles

Smooth muscle VS Striated muscle

Skeletal muscles are composed of?

The muscle fiber membrane contains receptor sites for? Which helps?

Each action potential produces a?

Answer 10

Smooth muscle - digestive tract, within arteries, and in the reproductive system

Striated muscle: can be either Cardiac muscle OR Skeletal muscle

Skeletal muscles are composed of many individual muscle fibers.

The muscle fiber membrane contains receptor sites for acetylcholine (ACh) - helps AP/contract and without relax - junction

Each action potential produces a single contraction or twitch.

Question 11

Organization from largest to smallest:

Answer 11

Muscle
Fascicles (nerve)
Muscle Fibers (CELLS)
Myofibrils
Sarcomeres
Myofilaments

Question 12

Slow-twitch fibers (Type I)

example for running?

what oxygen?

what activities?

Answer 12

example for running? marathon

Aerobic metabolism requires oxygen
Aerobic- Requiring the use of oxygen during movements.

Endurance activities, flying

Question 13

Fast-twitch fibers (Type II)

example for running?

what oxygen?

Two types fibers a VS b?

Answer 13

example for running? sprinters speed not endurance

Anaerobic- Proceeding without using oxygen at the time of a reaction.

Two types
Type IIa fibers – fast-twitch, fatigue-resistant fibers
Type IIb fibers – fast-twitch, fatigable(tired) fibers

Question 14

The Effects of Exercise on Muscle

Exercise builds muscle: how?

Lack of activity produces muscle changes: what?

The Effects of Aging on Muscles:
what age? which fiber lost?

Answer 14

Exercise builds muscle:
Muscle fibers are damaged
More actin and myosin filaments are produced

Lack of activity produces muscle changes:
Space travel
Spinal cord injury - paralyzed

The Effects of Aging on Muscles:
Muscle mass diminishes to about 50% of age 25 levels by age 80.
Selective atrophy of Type II fibers - sprinting
Age-related changes also occur in the neurons that control muscles.

Question 15

Motor neurons are not evenly distributed throughout the spinal cord: Cervical vs
Lumbar

Answer 15

The lumbar(lower legs) enlargement is bigger than cervical(upper hands) enlargement due to greater # of neurons that go to hands and legs

Question 16

Motor unit?

Motor neuron pools?

Neuromuscular junction?

Answer 16

Motor unit - Each muscle fiber receives information from one axon, but a single axon may innervate many muscle fibers. one axon innervates three muscles in eyes but bicep has one axon to more than 100 fibers. All the motor units serve a single muscle. All neurons for that muscle like triceps.

Motor neuron pools - collection of motor neurons that innervate a whole muscle tricep or quad

Neuromuscular junction
Highly efficient connection
Synapse between ACH and muscle

Question 17

To respond appropriately, alpha motor neurons require input from three types of neurons and state of body and environment: ?

Muscle spindle? source of information about? Lie parallel to the?

Golgi tendon organs in tendon? sense? protect? feedback?

Answer 17

• Neurons from muscle spindles and Golgi tendon organs
• Neurons of the brainstem and motor cortex
• Spinal interneurons
• Proprioceptors telling you about yourself so hungary full etc inside world

Muscle spindle - stretch of muscle feedback and length so not ripped apart
Embedded in the muscle that serves as a source of information about muscle length.
Lie parallel to the extrafusal fibers, so that when the muscle stretches, so do its associated spindles.

Golgi tendon organs in tendon - proprioceptor to sense what is going in muscle to prevent damage - muscle contraction so tension how much weight lifting how heavy for protection so don’t rip or damage muscle. Need feedback regarding the degree of muscle contraction, or force.

Question 18

​​The Patellar Tendon (Knee-Jerk) Reflex

What type of Reflex?

Answer 18

Contraction in response to sensing stretch is known as a myotatic reflex. A type of myotatic reflex is the patellar tendon or knee-jerk reflex. Hit knee at doctors.

Question 19

Monosynaptic reflexes VS Polysynaptic reflexes?

The Flexor Reflex?

Answer 19

Monosynaptic reflexes:
Reflex that requires the interaction of only two neurons at a single synapse.
Myotatic reflexes - knee

Polysynaptic reflexes:
Involve more than one synapse
Maintain posture
Prevent injury
Coordinate movement of limbs
Reciprocal inhibition for flexor and extender
Flexor

Flexor reflex- A polysynaptic spinal reflex that produces withdrawal of a limb from a painful stimulus.

Question 20

Antagonistic muscles? joint has? moves?

Flexor vs Extensor?

Reciprocal inhibition for?

Babinski sign?

Answer 20

Antagonistic muscles - move arms and legs back and forth. Each joint has at least one pair of antagonistic muscles, one flexor and one extensor.

Flexor - to body

Extensor - extend out away from body

Reciprocal inhibition for flexor and extender - polysynaptic reflex

Babinski sign - born with and should dispenser at certain age so not normal to have as a adult - neurological disorder - curl toes show happen when tickle foot not go out and up - your big toe lifted and your other toes spread out. A positive Babinski sign is normal for children under 2 years of age. It’s abnormal for children older than 2 years or adults.

Question 21

Alpha motor neurons (gray) in the spinal cord receive direction from?
Contract movement and release Ach

Answer 21

Alpha motor neurons(gray) in the spinal cord receive direction from the cerebellum, basal ganglia, red nucleus, brainstem, and cerebral cortex.
Contract movement and release Ach
Multiple parallel pathways communicate from one level of the motor system to the next.

Question 22

Motor neurons in the spinal cord can be located according to their roles as serving?

The brain manages movement of the head and neck through the?

Signals from the brain to the spinal alpha motor neurons in spinal travel along two routes:?

L includes
Corticospinal Tract
Rubrospinal tract

V inlcudes Four pathways stimulate alpha motor neurons:
Tectospinal tract
Vestibulospinal tract
Pontine reticulospinal tract
Medullary reticulospinal tract

Answer 22

Motor neurons in the spinal cord can be located according to their roles as serving flexors(dorsal located) and extensors and whether they serve proximal(in close) or distal(out) parts of the body.

The brain manages movement of the head and neck through the corticobulbar tract - contract primary motor cortex to spinal nerves/cranial nerves

Signals from the brain to the spinal alpha motor neurons in spinal travel along two routes: Lateral and Ventromedial Pathways Provide Input to the Alpha Motor Neurons

Lateral pathways: lateral part of the spinal column. Controls fine movement of hands, feet, and outer limbs - extremities.
– Includes
Corticospinal Tract: Originates in primary motor cortex travels through brainstem to opposite side of body bc right hand controlled by left hemisphere, Synapses on alpha motor neurons, Large, fast, and long
Rubrospinal tract: Originates in red nucleus - midbrain motor area and crosses over to other side and controls movement for opposite side of body. Synapses on alpha motor neurons. Input from cerebral cortex and cerebellum

Ventromedial pathways: Located along the ventromedial spinal column.
Manages automatic movements in the neck, torso, and portions of the limbs close to the body. Maintain posture and muscle tone
Moving head in response to visual stimuli.

Four pathways stimulate alpha motor neurons:

Tectospinal tract - tectum of midbrain to spinal cord for vision (hand eye coordination)

Vestibulospinal tract - vestibular of medulla

Pontine reticulospinal tract - recturial formation and pons to alpha

Medullary reticulospinal tract - recturial formation and medulla to alpha

Question 23

The Cerebellum?

Basal Ganglia Participate in? Consist of? The basal ganglia interact with the thalamus via two pathways:?

Answer 23

The Cerebellum: Maintenance of balance and coordination.
Learning of motor and other skills.
Important role in the sequencing of complex movements.
Informs the motor cortex about the direction, force, and timing required to carry out a skilled movement.

The Basal Ganglia Participate in Voluntary Movements:
Caudate nucleus
Putamen
Globus pallidus
Nucleus accumbens
Subthalamic nucleus
Involved with the choice and initiation of voluntary movements.
The basal ganglia interact with the thalamus via two pathways:
A direct pathway excites the thalamus
An indirect pathway inhibits the thalamus

Question 24

Supplementary motor area (SMA) VS Premotor cortex function?

Primary motor cortex (M1) is located in the precentral gyrus:?

Answer 24

the supplementary motor area (SMA) is mainly involved in internally-triggered movements, whereas the premotor cortex (PM) is highly responsible for externally-guided movements.

Primary motor cortex (M1) is located in the precentral gyrus: lies just anterior to the somatosensory cortex.
Main source of voluntary motor control
Direct connections with alpha motor neurons
Influences other motor pathways
Motor homunculus

Question 25

The Initiation and Awareness of Movement
What happens when we decide to move?

Answer 25

The brain makes a commitment to a choice of movement as many as 10 seconds before we become consciously aware of the decision.
This delay is needed by higher level systems to prepare for an upcoming movement.
Imaging technologies have been used to track the initiation of movement in human volunteers.
Participants were asked to carry out movements of the fingers from memory.
The first areas to show increased activity were the frontal and parietal lobes planned in SMA and premotor cortex incorporating input from thalamus and BG. Then the primary cortex sends signals via the lateral pathway then lateral pathways carry signals to spinal motor neurons which initiates muscle contractions.
These areas might be viewed as the parts of the brain that “think” about the movement and its consequences before the movement is initiated.
Theory: interpreter is in left hemisphere

Question 26

A variety of toxic substances interfere with movement. Neurotoxins Often Affect the Neuromuscular Junction

Cholinergic agonists VS Cholinergic antagonists

Sarin gas inhibits? - Neuromuscular Junction

Answer 26

Cholinergic agonists boost acetylcholine activity at the neuromuscular junction - Black widow spider venom

Cholinergic antagonists paralyze muscles - Venom of the Taiwanese cobra

Sarin gas inhibits acetylcholinesterase (AChE).
Muscles are continuously stimulated
Rapid fatigue and respiratory failure
New messages cannot produce movement

Question 27

Myasthenia gravis

Answer 27

Person’s immune system produces antibodies that bind to the nicotinic ACh receptor and starts in face

ACh receptors degenerate
Extreme muscle weakness and fatigue

Treatments:
Immunosuppressants bc autoimmune disease
Medications that inhibit AChE

Question 28

Muscular dystrophy? dystrophin? sex?

Duchenne muscular dystrophy?

Becker muscular dystrophy?

Answer 28

Muscular dystrophy - Group of inherited diseases characterized by muscle degeneration.
- Caused by abnormalities involving the protein dystrophin
- Sex-linked disorders typically affecting males(XY) bc on X

Duchenne muscular dystrophy
- No dystrophin at all
- Is typically fatal all muscle damaged

Becker muscular dystrophy
- Faulty dystrophin

Question 29

Polio?

Answer 29

Polio: is caused by a contagious virus that specifically targets and destroys spinal alpha motor neurons.
Symptoms can include muscle weakness and paralysis, usually of the legs.
If the infection affects higher levels of the CNS, breathing can be compromised.

Question 30

Accidental Spinal Cord Injury (SCI)
The spinal cord can be accidentally damaged when? quadriplegia?
lumbar region?

Answer 30

Accidental Spinal Cord Injury (SCI)
The spinal cord can be accidentally damaged when the protective vertebrae surrounding the cord are broken and compress or sever the cord itself.
If the damage occurs in the cervical, or neck, region of the spinal cord, the person will experience quadriplegia, or the loss of movement in both arms and legs.
If the damage occurs in the lumbar region of the lower back, the person will experience paraplegia, the loss of movement in the legs.

Question 31

Amyotrophic Lateral Sclerosis (ALS; Lou Gehrig’s Disease)

Answer 31

ALS results from the degeneration of motor neurons in the spinal cord, brainstem, and motor cortex.
The muscles served by these motor neurons degenerate when their input ceases.
Patients experience muscle weakness, and about 15 percent experience frontotemporal dementia.

Question 32

Parkinson’s Disease - not enough dopamine and it does not cross BBB ?

Causes remain unknown?

Drug treatment of choice: ?

Answer 32

A progressive difficulty in all movements, resting tremors, and frozen facial expressions.
Difficulty initiating voluntary movements.
Reflexive movements are also impaired.
This disease occurs when the dopaminergic neurons of the substantia nigra in the brainstem begin to degenerate.
The substantia nigra forms close connections with the basal ganglia.
The end result of degeneration is a lack of typical dopaminergic activity in the basal ganglia.

Causes remain unknown
Genetics play a role in early-onset but not in late-onset
Exposure to environmental toxins
Head injury
Correlation with lack of coffee use

Drug treatment of choice: L-dopa (pre curser to dopamine and does cross BBB so it goes all over brain and that can lead to side effects)
Surgical treatments: pallidotomy, thalamotomy, electrical stimulation
Stem cell transplantation

Question 33

Huntington’s Disease?

Caused by?

Huntington’s disease causes degeneration of?

Heredity and Presymptomatic Testing: ?

C-A-G Repeats and Huntington:?

Answer 33

Genetic disorder that usually strikes in middle age and produces involuntary, jerky movements. will get it or not and when age bc gene. No cure or effective treatments

Caused by abnormality in the Huntingtin gene on chromosome 4. Dominant gene, Abnormal proteins accumulate in basal ganglia

Huntington’s disease causes degeneration of the caudate nucleus of the Basal Ganglia.

Heredity and Presymptomatic Testing:
Presymptomatic tests can identify with high accuracy who will develop the disease.
The critical area of the gene includes a sequence of bases C-A-G (cytosine, adenine, guanine), which is repeated 11 to 24 times in most people.
The higher the number of consecutive repeats of the combination C-A-G, the more certain and earlier the person is to develop the disease.

C-A-G Repeats and Huntington:
A variety of neurological diseases are related to C-A-G repeats in genes.
In each case, people with the greatest number of repeats have the earliest onset of disease .
Those with a smaller number will be older, if they get the disease at all.
Recall that the genetic contribution is greater for early-onset than for late-onset Parkinson’s disease.

Question 34

Homeostasis?

Set point?

Allostasis?

Motivation: drive vs Incentive?

Answer 34

Homeostasis - Temperature regulation and other biological processes that keep certain body variables within a fixed range.
- A precisely defined set point
- Mechanisms for detecting deviations away from the set point
- Internal and behavioral elements designed to regain the set point

Set point - single value body works to maintain - deviation from set point will sweat, shiver, or paint so motivated behavior back

Allostasis - adaptive way body anticipates your needs so thirsty not dehydrated just avoid errors so not have to correct later

Motivation:
Drive (push) theories - Organisms are pushed toward a goal to reduce tension and discomfort (hunger/thirst is not comfortable so motivated to find food or water)
Incentive (pull) theories - Organisms are pulled toward a goal by the anticipation of rewards or incentives (chocolate cake not relieve hunger pain or anticipating dopamine for cake)

Question 35

An average young adult expends about 2300 kilocalories (kcal exercise and calories food) per day. Where does all that energy go?

Surface-to-Volume Ratios:
The higher an animal’s surface-to-volume ratio?
Who has larger surface-to-volume ratios?

Answer 35

Where does all that energy go? Basal metabolism
Basal metabolism - used to maintain constant body temp when at rest and most energy

Surface-to-Volume Ratios:
– The higher an animal’s surface-to-volume ratio, the harder it must work to maintain core temperature so more energy
— Rats have larger surface-to-volume ratios than humans or elephants.

Question 36

Endothermic (Homeothermic) example?

Endotherms have automatic?

Responses to lower temperatures:?

Responses to higher temperatures:?

behavioral mechanisms like ?

How warm is too warm?

Tardigrades?

Reproductive cells require a?

Answer 36

Endothermic (Homeothermic) human warm blood - temp constant

Endotherms have automatic internal responses to deviations from the temperature set point.

Responses to lower temperatures:
Shiver
Blood vessels constrict
Thyroid hormones increases to boost metabolic rate

Responses to higher temperatures:
Perspiration, licking, panting
Blood vessels dilate near skin surface

We also use behavioral mechanisms like ectothermic animals - humans put on sweaters go in shade

We spend about two-thirds of our total energy maintaining body temperature (basal metabolism).

How warm is too warm? Above 105f proteins break bonds - bird is 105

Tardigrades are indestructible and live in extreme conditions

Reproductive cells require a cooler environment than the rest of the body.

Question 37

Ectothermic (Poikilothermic)?

Ectothermic animals: surviving in extreme cold
Death will occur if body temperature drops below freezing?

Amphibians and reptiles avoid risk of cold using several methods. ?

An ectothermic animal, with a much lower level of basal metabolism, needs?

Birds and mammals keep their bodies warm at? Iguana cold day vs hot day?

Answer 37

Ectothermic (Poikilothermic) - temp is regulated behaviorally and don’t need as many calories - temp not maintained

Ectothermic animals: surviving in extreme cold
Death will occur if body temperature drops below freezing.
If body temperature drops below the freezing point of water, ice crystals form.
Ice crystals tear apart blood vessels and cell membranes, killing the animal.

Amphibians and reptiles avoid risk of cold using several methods:
Withdraw fluid to store in ECF
Antifreeze stock blood with at start of winter - chemicals cause ice crystals to form and not chunks no water freeze inside cell bc rip cell membrane so antifreeze makes not sharp crystals makes slush and they will withdraw most into extracellular not inside merbane
If damage blood clot which repair

An ectothermic animal, with a much lower level of basal metabolism, needs far less fuel.

Birds and mammals keep their bodies warm at all times, regardless of air temperature, and stay constantly ready for vigorous activity. Iguana cold day fight predator but hot day run bc dont have energy

Question 38

Fever?

Hyperthermia (heat stroke)?

Hypothermia?

Answer 38

Fever - immune system works more but above 103 or 104 is doing more harm than good

Hyperthermia (heat stroke)- A life-threatening condition in which core body temperature increases beyond normal limits.

Hypothermia is a potentially fatal core body temperature below 95F.

Question 39

Brain Mechanisms for Temperature Regulation

POA/AH does what? receives input from?

who is hot and who is cold?

Immune system delivers what to the POA?

Answer 39

Preoptic area (POA) of the hypothalamus, (along with adjacent areas of the anterior hypothalamus (AH) and septum), coordinate info from thermoreceptors with structures that trigger responses to higher core temps. - informing body to shiver, pant, sweat and damage means no sweat or shiver
Posterior hypothalamus responsible for initiating responses to cooler core temps.

POA receives input from temperature receptors in the skin, in the organs, and in the brain especially from the POA/AH itself.

Immune system delivers prostaglandins and histamines to the POA.

Question 40

POA contains 3 types of neurons interact to respond to changes to the temperature set point:

Answer 40

Warm-sensitive neurons 30% (inhibit cold sensitive ones) warmer so send more AP and will inhibit the cold sensitive. These receptors respond directly to changes in the temperature of the brain and blood in their vicinity.
Warm-sensitive neurons maintain a background level of activity that increases sharply when core temperatures surpass 98.6 F. - active and when fires inhibits cold from firing so warming the more freq the firing and when cold the firing goes down and the cold can now increase bc less inhibition (cold only active when warm are not) (inhibit the inhibitor than excitation)

Cold-sensitive neurons 5% in posterior hypothalamus - as get colder the warm will fire less so the cold will fire more - seesaw. Cold-sensitive neurons receive inhibitory input from the warm-sensitive neurons.
As core temperature drops below 98.6 F the reduced activity of the warm-sensitive neurons results in less inhibition of the cold-sensitive neurons, allowing them to increase their activity.

Temperature-insensitive neurons 60% are baseline(24/7 control) in the posterior hypothalamus.
These neurons maintain a steady rate of responding under all temperature conditions, yet they do have a role to play in thermoregulation.
Input from the temperature-insensitive neurons provides a baseline of activity in the cold-sensitive neurons that is modified by the amount of inhibition provided by the warm-sensitive neurons.

Question 41

Brain Mechanisms for Temperature Regulation Fevers due to illness: Pyrogens entering the brain increase the body’s temperature set point, causing fever.

POA? prostaglandin?

Answer 41

Once in the POA, pyrogens stimulate the release of prostaglandin E2, which in turn inhibits the firing rate of warm-sensitive neurons (warm slow not inhibiting cold so now body thinks it is cold, not true the body is not actually cold caused by pyrogens)

Reduced activity in the warm-sensitive neurons disinhibits the cold-sensitive neurons, increasing their activity, which fools the system into thinking the body is too cold.

The hypothalamus responds by raising the temperature set point.

Pyrogens Reset the Temperature Set Point in Fever

Question 42

Molecules that have been dissolved in a fluid are known as solutes and the fluid that contains the solutes is known as a solution.

The body’s fluids are held in several compartments:
Intracellular fluid?
Extracellular fluid?
Isotonic solutions?

Answer 42

Intracellular fluid: cytoplasm

Extracellular fluid contains body fluids in several compartments:
Interstitial fluid
Blood supply
Cerebral spinal fluid

Isotonic solutions have equal concentrations of solutes for osmotic thirst
Example: Some intravenous (IV) fluids

We typically stop drinking long before water levels in either the intracellular or extracellular compartments return to normal.

Question 43

Osmosis?

Hypotonic?

Hypertonic?

Any excess sodium or water is excreted by?

The Sensation of Thirst? Drop in fluid levels initiates two processes:?

Answer 43

Osmosis- Water moves from an area of lower solute concentration to an area of higher solute concentration. Osmosis Causes Water to Move.

Hypotonic solutions have a lower concentration of solutes compared to a reference solution.

Hypertonic solutions have a higher concentration of solutes compared to a reference solution.

Any excess sodium or water is excreted by the two kidneys, located in the lower back.

The Sensation of Thirst - do not need 8 glasses of water a day will get from foods and other stuff
Animals vary in their need to take in water.
Drop in fluid levels initiates two processes:
Sensation of thirst
Conservation of remaining fluids

Question 44

The Kidneys

Answer 44

Blood enters the kidneys, where it is filtered through a complex system made up of more than a million structures known as nephrons.

Impurities and excess water and sodium are removed by the nephrons and sent to the bladder for excretion as urine.

The filtered blood returns to the circulation.

We lose water through several other normal body processes.

Question 45

Osmotic Thirst

Answer 45

The higher salt content makes the blood hypertonic, or more concentrated, relative to the intracellular fluid.

Osmotic pressure will move water out of the cells to regain the balanced, isotonic state.

Receptors sense the lower volume of water in the cells, and you begin to feel thirsty.

Cellular dehydration is detected by specialized osmoreceptors in the brain.

An area located around the third ventricle, the organum vasculosum of the lamina terminalis (OVLT), along with surrounding areas of the hypothalamus, detect cellular dehydration.

The OVLT is a good place to detect blood solute levels
because the blood–brain barrier is weak in this area.

Animals with osmotic thirst have a preference for pure water.

Question 46

Hypovolemic Thirst

Answer 46

Lower blood volume is sensed by receptors in the heart and kidneys.

As blood volume decreases, blood pressure decreases as well.

The wall of the heart muscle contains baroreceptors that measure blood pressure.

The kidneys contain blood flow receptors that also respond to changes in blood volume.
When low blood volume is perceived, thirst is initiated, and the kidneys act to conserve remaining fluids.

Animals with hypovolemic thirst have a preference for slightly
salty water (sodium-specific hunger).

Question 47

Responding to Thirst

antidiuretic hormone (ADH), also known as vasopressin?

renin triggers the conversion of?

Angiotensin II?

Answer 47

When either cellular dehydration or hypovolemia is sensed, a sequence of hormone actions helps return fluid levels to their set point.

Both osmoreceptors and baroreceptors stimulate release of antidiuretic hormone (ADH), also known as vasopressin, by the posterior pituitary gland located just below the hypothalamus.

ADH signals the kidneys to reduce urine production to conserve fluid.

Stimulates kidneys to release hormone renin into the blood supply.

Once in the bloodstream, renin triggers the conversion of angiotensinogen, a blood protein, into angiotensin II.

Angiotensin II constricts blood vessels, helping to maintain blood pressure.

Angiotensin II also triggers the release of the hormone aldosterone from the adrenal glands, located above the kidneys.

Aldosterone signals the kidneys to retain sodium rather than excrete it in the urine.

Question 48

Animals vary in their eating strategies?

Answer 48

Animals vary in their eating strategies.
Predators have large digestive systems adapted to huge, infrequent meals.
Small birds eat only what is needed at the moment - so they can fly

Question 49

The Process of Digestion - Digestive system function is to break down food into smaller molecules that the cells can be used.

steps starts at mouth ends at large?

The hormone cholecystokinin (CCK) is released when?

Proteins are broken down into ?
Carbohydrates are broken into ?
Excess glucose is stored ?
Excess fat is stored in ?

If the body requires more energy than can be supplied by the glucose circulating in the blood, such as during a period of fasting, the liver converts?

If continued fasting depletes stores of glycogen, all body structures except the brain begin to?

Energy for the brain can be supplied by?

In addition, fasting causes muscle tissue to break down, and the liver converts the resulting?

Answer 49

Mouth digestion begins - salavea chewing
Stomach hydrochloric acid to digest proteins and breakdown
Small intestine - digest first place into blood stream abosrb
Large intestine - water and minerals absorb leftover from small
Large small extract into blood if not leave stomach

The hormone cholecystokinin (CCK) is released when large quantities of fat are consumed. Also signal fullness

Proteins are broken down into amino acids and used by muscles and other tissues for growth and protein synthesis.
Carbohydrates are broken into simple sugars, including glucose.
Excess glucose is stored as glycogen in the liver.
Excess fat is stored in adipose tissue.

If the body requires more energy than can be supplied by the glucose circulating in the blood, such as during a period of fasting, the liver converts stored glycogen back into readily available glucose.

If continued fasting depletes stores of glycogen, all body structures except the brain begin to use fatty acids from adipose tissue for energy.

Energy for the brain can be supplied by ketones, chemicals produced from stored fat by the liver.

In addition, fasting causes muscle tissue to break down, and the liver converts the resulting amino acids into glucose.

Question 50

The Pancreatic Hormones

The body’s supply of energy from glucose is regulated by hormones?

Glucagon converts stored glycogen ?

Insulin assists in moving glucose from the blood supply into ?

diabetes type 1 vs type 2

Without normal insulin function, glucose from food circulates through the bloodstream without?

Effects of Steady High Insulin Levels on Feeding: order?

Answer 50

The body’s supply of energy from glucose is regulated by hormones, glucagon and insulin, made by the pancreas.

Glucagon converts stored glycogen back into glucose.

Insulin assists in moving glucose from the blood supply into body cells and helps store glucose as glycogen. Need insulin to get nutrients into cells

Type 1 diabetes mellitus occurs when insulin-producing pancreatic cells are attacked and destroyed by the body’s immune system. - remain hungry even though ur eating cells are starving - autoimmune

Type 2 diabetes mellitus is when individuals produce insulin but their bodies either do not make enough insulin or do not use insulin efficiently—a condition known as insulin resistance. Produce insulin but body just ignores it - lifestyle choice
difference and what happens if give leptin they ignore it who does it - more fat more lepitn

Without normal insulin function, glucose from food circulates through the bloodstream without being absorbed or stored by the body’s tissues.

Effects of Steady High Insulin Levels on Feeding: eating - blood glucose increases and insulin level is high - insulin helps glucose enter cells and hunger temporarily decrease - blood glcuose levels decline but insulin levels do not - rapid return of hunger - then eating again

Question 51

The initiation of eating - why do we eat

Glucose hypothesis:

Lipostatic theory

lateral hypothalamus (LH)?

Answer 51

Glucose hypothesis:
Hunger can occur as a function of blood glucose levels.
Glucose levels in the blood are high just following a meal.
As glucose levels drop, a person begins to feel hungry again.
Glucose levels are intimately tied to insulin levels.

Lipostatic theory
Receptors in liver monitor fatty acids
If hunger results from low levels of available glucose and fats, receptors must assess nutrient levels and communicate with areas of the brain that initiate feeding behavior.
Glucoreceptors in the liver influence the release of insulin from the pancreas.
Find in hindbrain the medulla and liver

Rats with lesions in the lateral hypothalamus (LH) would starve to death in the presence of food because they would not initiate eating.

Question 52

leptin?

ghrelin?

Orexins (hypocretins) are produced in the lateral hypothalamus.?

leptin levels are high vs low?

Answer 52

After identifying the responsible gene, researchers found the peptide it makes, leptin. - the more leptin the less hungry and the more fat cells the more leptin, high levels of leptin say eat less, high levels leptin increase activity bc u have enough fat, hibernation and when pregnant ha slow leptin sensitivity bc need to eat more
Long-term hunger regulation is accomplished by the monitoring of fat supplies by the body.
The body’s fat cells produce the peptide leptin.

The hormone ghrelin is produced primarily by the pancreas and the lining of the stomach.
Receptors for ghrelin are found in the arcuate nucleus and the ventromedial hypothalamus.
Levels of ghrelin are highest during fasting and decrease following a meal.

Orexins (hypocretins) are produced in the lateral hypothalamus.
Injection of orexins into the hypothalamus results in increased eating in rats.
Levels of orexins are higher following food deprivation. Orexin cells are also stimulated by ghrelin, which again should lead to feeding.

leptin levels are high vs low:
When leptin levels are high, indicating sufficient fat is stored, the orexin cells are inhibited, and feeding is reduced.
When leptin levels are low, indicating fat stores are low, the orexin cells are active, orexins are released, and feeding is stimulated.

Question 53

Assessing Satiety

Main signal to stop eating is

Cholecystokinin (CCK)?

Brain mechanisms for satiety: less straightforward and understood than initiating eating

release of NPY?

Answer 53

Main signal to stop eating is the distention of the stomach.

The arrival of foods containing fats and proteins at the duodenum signals the release of the peptide CCK.
CCK promotes the release of insulin by the pancreas and contracts the gallbladder to release bile to help break down fats.
CCK clearly contributes to feelings of satiety and injection with CCK antagonists increases eating.

Stress combined with a high fat diet increases release of NPY and increases appetite.
Sleep deprivation leads to overeating

Question 54

Weight Loss Techniques?

Fructose

Answer 54

The most successful treatments require a change of lifestyle, including increased exercise as well as decreased eating. Exercise helpful not strianous just constant like walking

Reduce or eliminate the intake of soft drinks. Even if diet soda (intuitive eating ruined with diet soda or zero calorie) why bc body doesn’t know how to deal with fake stuff

Fructose is sweeter than common table sugar, the hope was that people could satisfy their craving for sweets without as many calories. Fructose increase people’s problem stored in fatty liver but glucose stimulates release of leptin and glucrion to make hungry - fructose gain calories without feeling satisfied
In one study, rats mostly ate the usual laboratory diet, but sometimes one group ate naturally sweetened yogurt while the other group ate yogurt sweetened with saccharin (noncaloric) they gained more weight