HMX second half flashcards

Transmural pressure

Ptm = Pi - Po

Pressure difference between inside and outside of a wall that determines volume of a flexible object

Balloon underwater size explained

Balloon gets smaller underwater.

Pi increases because elastic forces stay constant but pressure outside increases

Po increases and by larger factor

Ptm will decrease when underwater

What happens to transmural pressure along a tube

Decreases in the direction of flow as energy is lost over time when work is done to overcome resistance

static conditions

when pressure equalizes

what happens if pressure inside a tube is less than pressure outside

The tube would collapse and flow would stop

Critical pressure (Pcrit)

When the outside pressure exceeds the internal pressure of a biological tube and it collapses, halting flow.

Ptm of heart and BP relationship

Ptm is proportional to size of heart.

Size of heart is proportional to Q

Q is proportional to BP

Ptm of heart and Bp are proportional

Pthorax during forced exhalation

Pthorax increases as muscles in the abdomen and chest wall, contract to force extra air out.

oscillating tube (airway) process

Pi > Po → Pi decreases in direction of flow → Pcrit is reached and airway collapses, stopping flow → static conditions are regained → Pi returns to initial pressure where Pi > Po

Emphysema

Lung disease often caused by smoking that breaks down alveolus causing shortness of breathe, coughing, and wheezing.

Bleb

Blister like air pocket on surface of lungs. These are cut off from airflow maintaining a constant Pi. People with these are sensitive to external pressure change as they may burst and result in a collapsed lung.

Steady state

Input + Production = Elimination

Body holds a constant concentration of a substance that is taken in or made by cells and then excreted at an equilibrium.

Dynamic state

Input, production, or elimination increase or decrease to throw off equilibrium.

Graph of conc/time

• Steady State: Graph is a flat line at a certain height depending on conc.

• Dynamic state: Graph is either increasing or decreasing

Body response to dynamic state

The body has mechanisms to try and reestablish stable state when concentration of substance is increasing or decreasing.

PCO2 relationship

PvCO2 = 45mmHg

PaCO2 = 40mmHg

Venous CO2 is greater as this consists of arterial CO2 and the CO2 that muscle tissue produces as a by-product of metabolism. The arterial CO2 being less is important to create a concentration gradient that drives CO2 back into lungs from blood during exhalation.

Example of one lung being blocked off and regaining steady state

When one lung is blocked off, less CO2 is able to exit the body therefore increasing bodily concentration resulting in a dynamic state. The PCO2 of blood would increase with higher concentration in body so the single lung would compensate by increasing concentration of CO2 diffusing through it.

Bodily pH range and significance

7.36-7.44

Range in which enzymes can function properly

Three systems body uses to maintain pH

Buffer systems, respiratory system (lungs), and renal system (kidneys)

Carbonic acid equilibrium

CO2 + H2O <> H2CO3 <> HCO3- + H+

reversible chemical system to maintain bodily pH

Respiratory acid and how its produced

CO2

aerobic CHO metabolism produces H2O and CO2 that enter bloodstream

Respiratory acidosis

Drop in body pH due to over accumulation of CO2

Respiratory buffer system

• CO2 enters blood and diffuses into RBC

• CO2 reacts with H2O to produce HCO3- and H+

• H+ binds to hemoglobin proteins on RBC

• HCO3- diffuses into bloodstream

Respiratory elimination

CO2 in blood is carried to lungs to be expelled through exhalation

Metabolic acids and what produces them

• Protein metabolism: SO4-, PO4-

• Fat metabolism: ketones-

• Anaerobic CHO metabolism: lactates-

metabolic acidosis

drop in body pH due to decrease in HCO3- concentration or increase of metabolic acids

Metabolic buffer system

• metabolic acids dissociate into anion and H+ in blood stream

• HCO3- binds to H+ in bloodstream for carbonic acid equilibrium to be driven towards production of CO2 and H2O

• CO2 in blood is carried to lungs to be exhaled

Metabolic elimination of acids

• anion is filtered in glomerulus and diffuses into renal tubule to be excreted via urine

• CO2 in blood diffuses into renal tubule cell and binds to H2O to drive carbonic acid equilibrium towards production of HCO3- and H+

• H+ diffuses into renal tubule lumen to be expelled via urine

• HCO3- diffuses back into bloodstream to be used as a buffer

Respiratory buffer vs metabolic buffer

• Hemoglobin is respiratory

• HCO3- is metabolic

Respiratory system vs renal system acid elimination efficiency

• Respiratory system takes minutes to adjust bodily pH

• Renal system takes hours to days to excrete acids and regenerate HCO3-

Common bodily electrolytes

• Cations: Na+ K+

• Anions: Cl- HCO3-

Anion Gap and range

difference between concentrations of bodily cations and anions representing any unaccounted for anions as a result of metabolic acids because body is electrically neutral

Range: 12-16

Elevated Anion Gap

Indicates an increase in unaccounted anions due to increased metabolic acid production. More anions unaccounted for will decrease common anion concentration and would mean metabolic acidosis

Homeostasis general process

Body has a set point that it tries to maintain. If a stimulus disrupts this than body compensates by prioritizing vital parts first, supplying energy and resources while sacrificing other parts

Avg. BP

below 120 / below 80

carotid artery

artery branching off aorta that leads to brain

coronary artery

There are three of them that branch off base of aorta and lead back to heart

Baroreceptor

Receptor in carotid artery that detects pressure changes. When BP changes it detects and sends signal to activator

Sympathetic nervous system

controls bodies fight or flight. If something brings body away from set point it will increase functions to adjust bodies baseline.

Parasympathetic nervous system

manages rest and decreases bodily functions to bring body back to homeostasis

Cardiac output equation

Q = HR x SV

cardiac output = heart rate x stroke volume

Ulcer causing blood loss homeostasis example

• When blood is lost BP drops

• Baroreceptors detect drop in BP

• sympathetic nervous system activates and responds

• Hormones such as epinephrine and norepinephrine are released to increase heart rate, heart contraction force, and vasoconstriction

• Cardiac output and SVR increase to bring up MAP

• Blood flow to other organs outside heart is reduced as peripheral vessels restrict

VE minute ventilation

how many L/min a person breathes

VA Arterial ventilation

how much gas is going in and out of air sacs in lungs supplied with blood

Acidemia

Body pH drops out of pH range due to increase acid concentration

Chemoreceptor (two types)

• Central: located in brain and detects pH, and PaCO2

• Peripheral: located in carotid artery ad detects pH, PaCO2, and PaO2

Opioid depressing respiratory system homeostasis example

• VE and VA drop increasing PaCO2

• Increased CO2 in blood leads to acid build up and a drop in pH (respiratory acidosis)

• Chemoreceptors detect drop in pH and increase in PaCO2 so signal sent to respiratory controller

• Respiratory controller is impaired due to drug

• Renal system helps to drop pH

• CO2 in blood diffuses into renal cells where it is converted to H+ and HCO3-

• protons diffuse into tubule lumen and exit body through urine

• HCO3- diffuses back into bloodstream to act as a buffer

• PaCO2 levels remain elevated but after some days, blood pH is restored