Respiration 1 Flashcards
Explain the steps in external respiration
- Ventilation or gas exchange between the atmosphere and air sacs (alveoli) in the lungs.
- Exchange of O2 and CO2 between air in alveoli and the blood in the pulmonary capillaries
- Transport of O2 and CO2 by the blood between lungs and tissue
- Exchange O2 and CO2 between the blood in the systemic capillaries and the tissue cells
forces in the chest
- Intrapleural fluid cohesiveness (stickiness)
- Transmural pressure gradient x2
[Atmospheric (760) - Intrapleaural (756)]
What is the average resting PO2 at systematic capillaries?
40 mm Hg (partially saturated hemoglobin)
Normal PO2 at pulmonary capillaries?
100 mm Hg (fully saturated hemoglobin)
The % hemoglobin saturation depends on the;
PO2 of the blood
Why Respiration?
- Oxidative phosphorylation for ATP
- To maintain viability
Respiratory surface area ________ with size
increases
General function of respiration
to obtain O2 for use by the body’s cells and to eliminate the CO2 the body cells produce
2 separate but related processes
Internal respiration
External respiration
Internal Respiration
[Cellular respiration]
- metabolic processes carried out within the mitochondria, which use O2 and produce CO2, while deriving energy from nutrient molecules.
Respiratory quotient (RQ)
The ratio of CO2 produced to O2 consumed
(in internal resp)
Varies depending on the foodstuff consumed
Brain, heart, muscle
External Respiration
Refers to the sequence of events involved in the exchange of O2 and CO2 between the external environment and the cells of the body
4 steps of external respiration
> Ventilation – movement of air into and out of the
lungs
O2 and CO2 are exchanged between air in alveoli
and blood within the pulmonary capillaries by
means of diffusion
Blood transports O2 and CO2 between lungs and
tissues
O2 and CO2 are exchanged between tissues and
blood by process of diffusion across systemic
(tissue) capillaries
Non-respiratory Functions of Respiratory System
- Route for water loss and heat elimination
- Enhances venous return
- Helps maintain normal acid-base balance
- Enables speech, singing, and other vocalizations
- Defends against inhaled foreign matter
- Removes, modifies, activates, or inactivates various
materials passing through the pulmonary circulation - Nose serves as the organ of smell
Pseudostratified columnar ciliated epithelium, trachea
Simple squamous epithelium (Mesothelium and Endothelium)
Simple squamous epithelium
Mesothelium and Endothelium
lining of body cavities
(mesothelium visceral and parietal)
Function: passive transport
Respiratory Airways
Tubes that carry air between the atmosphere and the air sacs
Respiratory Airways
- Nasal passages (nose)
- Pharynx (common passageway for respiratory and
digestive systems) - Trachea (windpipe)
- Larynx (voice box)
- Right and left bronchi
- Bronchioles
Alveoli (air sacs) are clustered at ends of
terminal bronchioles
GAs transfer occurs across the:
respiratory epithelium
Trachea and larger bronchi
Fairly rigid, non-muscular tubes
Rings of cartilage prevent collapse
Bronchioles
- No cartilage to hold them open
- Walls contain smooth muscle innervated by
autonomic nervous system - Sensitive to certain hormones and local chemicals
Thin-walled inflatable sacs
Alveoli
Function in gas exchange
alveoli
Alveoli cell walls consist of:
single layer of flattened Type I alveolar cells
encircle each alveolus
Pulmonary capillaries
Type II alveolar cells
secrete pulmonary surfactant
guard lumen
Alveolar macrophages
permit airflow between adjacent alveoli (collateral ventilation)
Pores of Kohn
Pulmonary artery
deoxygenated blood
pulmonary vein
oxygenated blood
Relationship of Resistance and Flow to Vessel Radius
Flow proportional to differential pressure and r4
Pressure gradient of blood flow
is pressure difference between beginning and end of a vessel
Blood flows from area of ________ pressure to area of ________ pressure
higher
lower
Resistance is:
a measure of the opposition of blood flow through a vessel
Resistance of blood flow depends on:
Blood viscosity
Vessel length
Vessel radius
Major determinant of resistance to flow is
vessel’s radius
Slight change in radius produces significant change in blood flow
R is proportional to 1/r4
Respiration:
for ATP’s sake to maintain cellular viability and function
Order of respiration
Air –> lungs –> capillaries –> tissue
diffusion in alveoli
500nm
How does the respiratory system contribute to homeostasis
- By obtaining O2 from and eliminating CO2 to the
external environment. - Helps regulate the pH of the internal environment
by adjusting the rate of removal of acid forming
CO2
Why is homeostasis of respiration necassary?
- Cells need a constant supply of O2 delivered to
them to support their energy-generating chemical
reactions. - These reactions generate CO2 that must be
continuously removed. - Furthermore, this CO2 generates carbonic acid with
which the body must deal with to maintain the
proper pH of the internal environment
> Cells can only survive within a narrow pH.
