PGY 206 Exam 4 UKY

Renal, Exercise, Respiratory

Work

effort used to move a mass

Work

force times distance

Exercise

work at faster rate

Work rate

work divided by time

What is the total body weight in a 100 lb female?

60 pounds

An increase in ---- activity causes contraction of the detrusor (bladder) muscle

Parasympathetic

Relaxation of this muscle in the urinary system is under voluntary control.

external urethral sphincter

which of the following two scenarios would each predict an INCREASE in glomerular filtration rate (GFR)?

vasodilation of the afferent arteriole OR vasoconstriction of the efferent arteriole

The sequential order of the blood flow through the nephron is best described as:

afferent arteriole- glomerular capillaries- efferent arteriole- peritubular capillaries

If a substance is filtered, secreted and completely reabsorbed in the nephron, how much is excreted?

NOTHING!

Which of the following substances is normally filtered in the glomerular capsule

glucose

A decrease in the osmotic force due to protein in the plasma will ----- the glomerular filtration rate

increase

The kidneys maintain a constant GFR despite systemic changes. If the mean arteriole pressure drops below 70 mmHg which of the following is most likely to occur?

vasodilation of afferent arteriole

A person who has renal failure most likely has

high plasma concentration of creatinine

Which of the following is TRUE about juxtamedullary nephrons?

They are critical for producing hypertonic urine

The juxtaglomerular apparatus consists of macula densa and granular cells. If plasma Na+ concentration is high then the release of ----- from granular cells will decrease

renin

Which of the following statements about inulin clearance is TRUE?

it is similar to the clearance of creatinine.

Urea clearance is normally ---- the GFR

less than

If the renal transport threshold for glucose is reached that means glucose ---- will increase

excretion

A person with Conn’s disease has an abnormally high level of aldosterone. The urine of this person most likely has lower than normal concentration of…

Na+

A person with Addison’s disease has very low levels of aldosterone. The plasma of this person most likely has higher than normal concentration of ------

K+

A person with altitude sickness (which causes hyperventilation) might benefit from which of the following diuretics?

carbonic anhydrase inhibitors

Diagram of juxtaglomedullary nephron: Normally all the filtered glucose is reabsorbed at this part of the nephron

B

The osmolarity of the ultrafiltrate decreases in this part of the nephron due to the reabsorption of Na+, K+, and Cl- and impermeability to water

C

The ultrafiltrate is formed at this part of the nephron

A

A decrease in antidiuretic hormone (ADH) signaling decreases water reabsorption at this part of the nephron.

E

About 90% of the filtered K+ is reabsorbed at this part of the nephron

B

About 40-60% of the urea is reabsorbed at this part of the nephron

E

This portion the nephron is permeable to water but not Na+, K+, or Cl-

D

Most of the reabsorption of filtered Na+ occurs in this part of the nephron

B

Which gas has the biggest increase in alveolar partial pressure when compared to that found in warm humid atmospheric air?

Carbon dioxide

Lung compliance is likely to be decreased by

increased fibrosis

For active expiration, which occurs first?

Expiratory muscles contract

At rest, what is the normal carbon dioxide partial pressure (PCO2) in the pulmonary artery of a healthy person?

46mmHg

Which value is about the same in both the pulmonary and systemic circulations?

total blood flow per minute

Which statement best describes ventilation-perfusion (v/q) matching in the lung of a standing individual?

The apex is underperfused

Which part of the brain is most important in determining the respiratory pattern for a person that is doing spirometric measurements like a forced vital capacity?

Cerebral cortex

Expiration of alveolar gas

can follow contraction of the expiratory muscles

Loretta breathes 10 times per minute; her tidal volume is 600 mL and her anatomic dead space is 300 mL. What is her alveolar ventilation?

3000 mL/min

The volume of air inhaled between the FRC (functional residual capacity) and a maximal inspiration is the:

Inspiratory capacity

Emphysema, a pulmonary blood clot, and lung cancer are all likely to:

decrease the surface area for gas exchange

Hemoglobin in systemic arterial blood is usually described as:

fully saturated with oxygen

The oxygen-hemoglobin dissociation curve

has a plateau portion that facilitates O2 loading in the lungs

The oxygen-hemoglobin dissociation curve is shifted rightward by increasing which property in the blood?

2, 3- DPG (BPG) content

The majority (70%) of CO2 in blood is transported in what form?

HCO3

When a patient secretes large amounts of mucus into the airways, you would expect the mucus to ----- the lumen of the conducting zone, ----- the resistance to airflow, and ---- the volume of the dead space.

narrow, increase, decrease

Which aspect of blood chemistry elicits the greatest increase in activity of the peripheral chemoreceptors?

Arterial PO2 less than 60 mmHg

When one visits a region at high altitudes, what is the primary sensed variable that leads to an increase in one’s minute ventilation?

systemic arterial PO2

What causes the partial lung collapse in a person that has pneumonia?

Transpulmonary pressure decreases

Which cell type is most likely to be abnormal in a prematurely born infant?

alveolar type II cells

Which brain region is most important in altering your breathing while watching a basketball game?

subcortical regions

Gas exchange across your lungs may be reduced by

congestive heart failure

Pulmonary surfactant

increases lung compliance

The pressure difference between the pressures in the atmosphere and in the alveoli is equal to

flow times resistance

Respiration term is used in 2 ways

1. Mitochondrial O2 utilization (aerobic metabolism)
2. Ventilation- aka breathing; gases move via bulk flow; conducting airways are essential

The thorax includes

chest wall, thoracic cavity, and pleural cavity

Chest wall includes

diaphragm: skeletal muscle sheet

Thorax: rib cage, spinal column, and trunk muscles

Thoracic cavity

contains lungs, trachea, heart, large vessels, esophagus, and thymus

Pleural cavity

space between visceral and parietal pleurae

Conducting zone:

1. conducts air flow (bulk flow) to respiratory zone
2. warms and humidifies inspired air
3. cleans air- secretes mucus, cilia move mucus, emphysema (smoking), cystic fibrosis (decrease cilia mobility)
4. ciliated epithelium

cystic fibrosis

Thick, sticky mucus blocks the airway

site of gas exchange

in some of the alveolar walls, pores permit the flow of air between alveoli

most air-facing surfaces of the alveoli wall are lined by a thin layer of water

continuous layer type 1 alveolar cells

Type II alveolar produce a detergent- like substance called

surfactant (lowers surface tension of water)

also involved in site of gas exchange

alveolar macrophages

Alveoli

1. Primary site of gas exchange
2. Approximately 300 million in adult lung, 60-80 m^2 surface area (tennis court)
3. barrier to diffusion is 2 cells across (2 micrometers)

Alveolar cell types

1. Type 1: epithelial cells with structural function (80-90% of cells) - thin and interconnected by pores
2. Type 2: secrete surfactant
3. Macrophages: clean debris

Respiratory zone includes

respiratory bronchioles and alveoli

air moves between in the respiratory zone (alveoli) via

diffusion

Respiratory pressures include

1. Intrapulmonary or alveolar pressure (Pa)
2. Intrapleural pressure (Ppl)
3. Transpulmonary pressure

Intrapulmonary or alveolar pressure

equals atmospheric pressure at rest

altered by changes in lung volume

Intrapleural pressure (Ppl)

subatmospheric (negative) at rest

determined by lungs and chest

Transpulmonary pressure

pressure difference across lung (PA-Ppl)

determines lung volume

Important pressures

1. Patm- atmospheric pressure (760 mmHg at sea level)
2. Patm-Pa= transairway pressure
3. Pa-Ppl= transpulmonary pressure

Pleural pressure (Ppl)

1. intrapleural pressure
2. pressure between chest wall and lung
3. Ppl is always more negative than Pa
4. Ppl is affected by forces of gravity

Boyle’s law

P1V1=P2V2

Ideal Gas Law

PV=nRT ( a constant if temperature and number of molecules is unchanged, a “closed container”)

Changes in lung volume alter intrapulmonary pressure (Pa)

gas pressure inversely proportional to container volume

With lung expansion, Pa falls below atmospheric pressure (Patm or Pm)

Air flows in

With lung compression, Pa increases above Patm

air flows out

During inspiration: Active process

* Diaphragm contracts, increasing thoracic volume
* Parasternal/external intercostals contract (accessory muscles), pulling the ribs up and out

During intrapleural pressure (Ppl) becomes

more negative

During inspiration, lung is pulled open…

increasing lung volume

During inspiration, Intrapulmonary pressure (Pa) becomes

more negative (subatmospheric)

During inspiration, air flows…

into lungs

Muscles of inspiration are:

sternocleidomastoid, scalenes, external intercostals, parasternal intercostals, and diaphragm

Muscles of expiration are:

Internal intercostals, external abdominal oblique, internal abdominal oblique, transversus abdominis, rectus abdominis