POUL 4200 Final Exam

POUL 4200 Cumulative questions for final exam. Tests 1, 2, 3 and 4.

TRAP

Assists with the removal of phosphate from Hydroxyapatite

CAH

Assists with acidic environment in resorptive pit

Cathespin K

Protease that degrades osteoid (collagen)

Vitronectin

Assists with formation of sealing zone

A mutation of ______ in a line of chicks showed that chickens have retained the pathway for forming conical and sabe shaped teeth

Talpid II

What calcium regulating hormone, produced by the ultimobranchial glands in birds, is increased when blood calcium levels are HIGH?

Calcitonin

What is Osteomyelosclerosis?

formation of medullary bone

____________ was just recently discovered to have a major role in the fight or flight response of vertebrates.

Osteocalcin

What type of epithelium would you find in the trachea?

Ciliated Pseudostratified epithelium

Which zone of the epiphyseal plate would respond the most to growth hormone?

Zone of proliferation

Which type of bone growth is responsible for and increase in diameter of bones?

Appositional growth

PTH causes _______________.

Increased bone breakdown

What protein is increased in response to calcitriol that facilitates the absorption of calcium in the duodenum and jejunum?

Calbindin

Osteoblasts synthesize ___________.

Alkaline phosphatase, collagen, and osteocalcin

_________ is the famous Bavarian transitional fossil that provides evidence for the evolutionary linkage between birds and theropods.

Archeopteryx

The oily secretion from this cutaneous glad is primarily used to condition feathers.

Uropygial gland

__________ are the bone-forming cells that synthesize bone matrix and can become trapped in the matrix to become __________.

Osteoblasts, osteocytes

_______ are the areas where feathers grow, while _______ are the areas where no feathers grow.

Pteryla, apteria

_______, primarily located in the osteogenic layer of the periosteum to give rise to osteoblasts.

Osteoprogenitor/msc

The levels of these two amino acids are critical to monitor for assuming good feather coverage in broiler breeders:

Methionine and cystine

Why do we have cartilage C-rings around our trachea, while birds have completely circular cartilage rings around their tracheas?

Our esophagus is located immediately dorsal (behind) to the trachea, resulting in c-shaped rings. Birds have a separated trachea and esophagus.

Provide three layers of the epidermis from superficial to deep.

Stratum corneum, Stratum spinoseum, and stratum basale

The _____ is the “voice box” of the bird.

Syrinx

Mechanical unloading (like being an astronaut) would lead to an increase in _______ being released by osteocytes.

Sclerostin

Name all the different air sacs found in a chicken.

Cranial, intraclavicular(1), Cervical(2), Anterior thoracic(2), Posterior thoracic(2), Abdominal(2)

The _______ is the organic, unmineralized portion of the bone matrix, made up of mostly collagen, that provides tensile strength. While ________ is the inorganic, mostly calcium and phosphorus, that provides compressive strength to the bone.

Osteoid, Hydroxyapatite

How would the following impact osteoclast activity?

RANKL

Sclerostin

Cortisol

OPG

PTH

Estrogen

RANKL- Increase

Sclerostin- increase

Cortisol- increase

OPG- decrease

PTH- Increase

Estrogen- decrease

Explain why evaluation of vit D levels test for 25 hydroxycholecalciferol instead of the active 1, 25 dihydroxycholecalciferol?

25 hydroxycholecalciferol is constantly being produced in the liver and reflects circulatory levels of Vit D3. The active form is tightly regulated and levels are more dependent on blood calcium levels.

Explain why large particle calcium is often included in layer feed formulations.

They are retained in the GI tract for much longer than smaller particles. Larger particles serve as calcium reserves for eggshells when hens are not eating.

Describe how Wolff’s law can explain cage layer fatigue. How would sclerostin be impacted by caged hens and how does this relate to cage layer fatigue?

Wolffs law: bone density decreases without load-bearing exercise. When layers have little-no exercise, sclerostin increases and this may lead to more fractures of bones.

Provide at least one adaptation for flight provided buy each of the following systems:

Digestive

renal

Cardiovascular

respiratory

Digestive: lack of teeth

Renal: Uric acid production so no H2O has to be stored.

Cardiovascular: High heart rate and large capacity of heart

Respiratory: air sacs to reduce centralized weight

Provide Two ways PTH increases with Calcium reabsorption.

In the kidney, TRPV6 is upregulated to cause an increase in reabsorption in proximal convoluted tubule.

In Intestines, calbindin is upregulated and is used as a chaperone protein to increase intracellular calcium concentration.

Why is it important to maintain relative humidity between 50 and 70% in a broiler house in regard to the respiratory system.

Cilia and parabronchi need moisture to function, while air that is too dry can cause dehydration. Too much humidity can increase moisture and ammonia levels in the house.

hen calcium concentration is low, PTH will increase hydroxylation at position _____, but when calcium levels are normal hydroxylation will occur at position ______.

1, 24

Name a location you would find non-keratinized stratified squamous epithelium.

Esophagus

Why do birds undergo the more metabolically demanding process of producing uric acid (instead of urea) as their nitrogen waste product?

In mammals urea is more toxic than uric acid and must be diluted with water to store it. Uric acid production reduces the need for water and reduces weight for flight.

Provide two anatomical differences between the avian respiratory system and the mammalian respiratory system.

Avian have lungs embedded in the ribs and they do not expand like humans. Avian also have parabronchi for cross-current exchange where humans have alveoli.

Despite knowing wolff’s law, explain why women that consistently run marathons may have increased risk for osteoporosis?

Estrogen plays an important role in regulating bone health. It inhibits the cells (osteoclasts) that break down bone. It reduces bone resorption by its effects on parathyroid hormone and calcitonin. Calcium is needed to build bone, and estrogen speeds up the absorption of calcium in the intestine and reduces calcium excretion. Women who run a lot put more energy towards physical performance than the making of estrogen so they have a lower amount of estrogen to use for bones.

On a molecular level, how could you distinguish between TD and rickets?

TD birds exhibit normal PTH1R and calcium levels, but birds with rickets have a decrease in PTH1R due to receptor desensitization from high PTH and low calcium.

Provide the pathway for synthesis of vitamin D(1, 25 dihydroxycholecalciferol) and indicate the rate limiting step and trigger to initiate pathway completion.

1. The diet delivers Vitamin D3 cholecalciferol

2. this goes to the liver where it is converted to 25 hydroxycholecaciferol by the secretion of 25-hydroxylase from the liver.

3. The kidney uses 1 alpha hydroxylase that PTH activates to convert 25 hydroxycholecaciferol to 1,25 dihydroxycholecaciferol or calcitriol

   *1 alpha hydroxylase is the rate-limiting step

Provide the pathway of air through the avian respiratory system. Start with entrance through nares during the 1st inspiration and end with the exit from the trachea.

a. how is this more efficient than mammals?

1. Nares to chonchae to glottis to trachea to syrinx to primary bronchi to intrapulmonary bronchi to abdominal air sacs

2. (1st exhale) abdominal air sacs to dorsobronchi to paleopulmonic bronchi

3. (2nd inhale) Paleopulmonic brinchi to ventrobronchi to front air sacs (intraclavicular, cervical, and cranial air sacs)

4. (exhale 2) front air sacs to primary bronchi to syrinx to trachea to glottis to outside

This is more efficient do to the cross-current exchange happening so that there is no air that has to sit in the repiratory system. Birds can extract 30% more oxygen this way than humans.

Which of the following is the most common location where action potentials originate in a motor neuron?

Axon Hillock

This protein is activated by the Calcium-calmodulin complex to induce smooth muscle contraction.

Myosin Light chain kinase (MLCK)

The main route of Sarin Gas toxicity is

Inhibition of Acetylcholinesterase

What coding system do neurons use to get a greater response?

Increased frequency of stimuli

Briefly explain why action potentials propagate in a unidirectional matter, from the soma of the motor neuron to the terminal bouton.

Neurons have an absolute refractory period in which they don’t respond to a stimulus for a period after being stimulated. Because of this, voltage gated sodium channels open in a unidirectional anterograde direction towards the synapse.

Explain how the arrival of an action potential at the terminal bouton leads to exocytosis of acetylcholine into the neuromuscular junction.

Action potentials provide the voltage required to open voltage gated calcium channels and make calcium bind to synaptotagmin where a complex is formed that inhibits SNARE protein binding to vesicles with acetylcholine and allow for exocytosis of acetylcholine.

When comparing complete tetanus to incomplete tetanus, which is true?

Complete tetanus involves development of maximum tension.

The function of transverse tubules is to

rapidly conduct action potentials to the interior of the muscle fiber

The calcium release channel in the smooth muscle sarcoplasmic reticulum that is opened by increase in phospholipase C activity is the

IP3 Receptor channel

Provide at least two ways metabolically active tissues increase oxygen loading from systemic arterioles.

1. The bohr effect: increases O2 unloading with H+ from CAH. This is because H+ binding to HbO2 reduces its affinity for oxygen and makes the hemoglobin release oxygen.

2. CO2 loading happens when CO2 diffuses into the blood and carbonic anhydrase in red blood cells catalyze and HCO3- is exchanged for Cl-

Explain why panting, or hyperventilation, would lead to poor eggshell quality.

Panting causes blood alkalosis because of the decrease in carbon dioxide in the blood and reduces the amount of CO2 that can be used for Calcium carbonate production for the eggshell.

Which molecule blocks the myosin head from binding to actin in a relaxed muscle?

Tropomyosin

The gap junctions in cardiac muscles are part of a specialized cell junction between myocardiocytes that are localized to the _________ _____.

Intercalated discs

What is the difference in the type of muscle fibers found in duck and chicken pec major? What is the reason behind this difference

Ducks have 28% type IIB and 72% type IIA

Chickens have 100% type IIA

Type IIB muscle fibers have increased myoglobin, vascularization and mitochondria which helps endurance for the metabolic demand of flight.

How would an intracellular increase of the following influence smooth muscle(contract or relax).

IP3

Nitric Oxide (NO)

MLCP

MLCK

IP3: Contraction

NO: Relaxation

MLCP: Relaxation

MLCK: Contraction

Explain the etiology of white striping and why it is common in broilers but almost never seen in any other poultry.

It is a myopathy of the pec major because of hypoxic conditions in the pec major and leads to localized necrosis and remodeling of myocardiocytes with collagen and lipids(white stripes). Broilers having been genetically selected for increased muscle hypertrophy than other poultry without improved vascularization causes hypoxia.

The calcium ions required for cardiac muscles to contract is mostly due to ___________.

Calcium ions released from RYR channels in the SR.

____________ is characterized by continued attachment of the myosin heads to actin filaments due to lack of ATP.

Rigor mortis

Type I fibers have an ________ oxidative capacity and a ________ glycogen content, relative to type II fibers.

High, Low

Each myosin head has a binding site for

actin and ATP

Acetylcholine is excitatory at the neuromuscular junction (motor end plate), but generates an IPSP at the SA node. Explain why.

SA node: Acetylcholine binds to M2 receptors at the SA node, M2 receptors, being a Gi, have alpha subunits which are dislodged by ACh and down regulates adenyl cyclase. This causes a decrease in cAMP and causes a lower HR. The beta and gamma subunits dissociated from M2 receptors and bind to ligand gated potassium channels to generate an IPSP.

Neuromuscular Junction: ACh is released by the upper motor neuron into the synaptic cleft where it will bind to nicotinic receptors. When binded, Na ions rush in to allow the generation of an EPSP to generate action potential.

Somatic motor neurons release the neurotransmitter_______ at the neuromuscular junction that binds with ________ receptors on the motor end plate.

Acetylcholine, nicotinic

___________ is a paracrine regulator that inhibits satellite cell function and muscle growth. (“knock-out” of this gene leads to double muscling)

ex: belgian blue cattle and whippet dogs

Myostatin

The most accurate definition of artery is a vessel that

transports blood away from the heart

The sac around the heart is the

pericardium

The AV node is important because it

delays the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting

The P wave of an ECG corresponds to

the depolarization of the atria

During ventricular systole

The AV valves are closed

_________ is an oxygen-binding molecule which contains a heme group and is responsible for the red pigmentation of “dark meat”

Myoglobin

Drugs that block beta-adrenergic receptors, known as beta blockers, would

decrease HR (bc of decreased cAMP)

A certain drug decreases heart rate by producing hyperpolarization in the pacemaker cells of the heart. This drug probably binds to

Muscarinic receptors

Name three blood circuits and which side of the heart feeds each circuit.

Coronary: Left ventricle (diastole)

Pulmonary: Right ventricle (systole)

Systemic: left ventricle (systole)

Explain why epinephrine binding to an alpha-1 receptor can induce vasoconstriction, while acetylcholine binding to muscarinic receptors can induce vasodilation. Note both alpha-1 and M1 are Gq-linked receptors.

Epi-alpha 1:

1. Epinephrine binds to the alpha 1 receptor of the Gq protein

2. This binding causes activation of phospholipase c

3. phospholipase c leads to production of IP3 which will increase intracellular calcium levels by triggering its release from the SR

4. Calcium will bind to calmodulin and create its complex

5. the complex trigger the activation of MLCK and causes vasoconstriction

ACh-M1:

1. Acetylcholine binding to muscarinic receptors causes the dissociation of the alpha subunit of the Gq receptor and increases cAMP.

2. the alpha subunit activates phospholipase c and increases IP3 production

3. Ip3 binds to its receptors in the endoplasmic reticulum and calcium is released into the cytoplasm

4. Calcium calmodulin compex is formed and activates NO synthesis

5. NO activates guanylyl cyclase and cyclic GMP

6. cGMP activates protein kinase G to cause vasodilation

Explain how cold stress during brooding is associated with an increase in ascites? provide the onset of the pathology and why it presents with increased abdominal fluid.

Cold stress means the chicks must utilize their energy to maintain body temperature and causes Increased T3 production. the corresponding affects is increased O2 demand of tissues, increased cardiac output to cause ventricular hypertrophy, and failure of right AV valve which causes backflow of blood to impede blood colloid osmotic pressure and fluid retention to cause fluid build up in the abdomen.

Provide two hromones (or neurotransmitters) that increase gastric secretions and one hormone that decreases gastric secretions.

Increase: Histamine, Acetylcholine

Decrease: CCK

The avian posterior pituitary secretes

Mesotocin

Thyrotropin-releasing hormone (TRH) targets the

anterior pituitary

Presence of irritants or toxins in ingesta will stimulate ECL cells to secrete ________ to increase gastric mobility and/or reverse peristalsis.

Seratonin

ADH (AVT in birds) targets the

Kidneys

The pituitary hormone that controls the release of glucocorticoids from the adrenal cortex is

ACTH

Which of the following best depicts the insulin receptor?

The insulin receptor uses a tyrosine kinase second messenger system.

Why is beak trimming used in some birds in poultry production?

Reduce the effects of cannibalistic activity, especially in those birds that are used for long-term production.(breeders or layers)

Which of the following is false concerning melatonin?

Exposure to light stimulates production

Low sodium in the diet of bids can lead to decreased absorption of

amino acids and monosaccharides

Secretion of this polypeptide by the gastric mucosa(parietal cells in mammals) is considered the only “vital” function of the stomach since it is required for absorption of the vitamin B12.

Intrinsic factor

The ______ secretes ________, which promotes sodium and water retention.

Adrenal Cortex, aldosterone

The enterocytes of the duodenum secrete this hormone that inhibits gastric secretions of the proventriculus (stomach) and stimulates secretion of digestive enzymes from the pancreas.

CCK

What is the function of the crop?

Storage and minimal digestion of food

Which hormone is NOT involved in gastric functions?

Glucagon

This enzyme would show increased activity in oxyniticopeptic (or parietal) cells in the presence of gastrin, histamine and acetylcholine.

Carbonic anhydrase

Cortisol _______________.

Promotes glycogenolysis

Many hours after a meal, alpha cells in the pancreatic islets secrete

glucagon, which raises blood glucose

A rise in cortisol would cause an increase in each of the following except:

An Increase in ACTH

What binds and transports thyroxine in chicken blood?

Albumen

In chickens, _________ stimulates the release of _________ to control seasonal breeding.

Melatonin, GnIH

In the absence of ligand, class I nuclear receptors are located ________.

In the cytosol

The thyroid hormone receptor must heterodimerize with _______ before the corepressor element can be removed.

RXR

This hepatic specific enzyme is required before glucose can be released through GLUT-2 receptors in liver cells.

Glucose-6-phosphatase

Histamine, working through a Gs receptor present on parietal cells, increases gastric acids secretion. Why might ingestion of caffeine potentiate more gastric acid secretion in parietal cells.

Caffeine is known to inhibit phosphodiesterase, the enzyme needed to reduce cAMP to AMP. Gs receptors also work to increase cAMP, which indicates that high levels of cAMP cause increased HCl and CAH production to increase H+ pumping.