Chapter 46: Respiratory System Flashcards
What is the outside structure of the trachea made of? inside linning?
outside made of chondrocytes/cartilage
inside made of pseduo-stratified epithelium/cilia
Which type of respiration do we focus on in this chapter?
physiological respiration
Composition of air?
21% oxygen, 78% nitrogen, less than 1% of CO2 and other gasses
What is 1kPa?
7.5 mmHg
What is atmospheric pressure?
sum of the partial pressures of each gas (pressures exerted by each gas in air) in proportion to their amounts
Why is the rate of oxygen diffusion into blood is lower at higher elevations?
Percentage of gases remain the same regardless of altitude, but lower atmospheric pressure results in lower partial pressures—lower amount of O2 molecules
Diffusion is driven by partial pressure gradients
What is Fick’s Law of Diffusion?
R = ( D A delta p) / (d)
What are some ways to increase diffusion?
thin membrane for diffusion, large SA, higher concentration gradients, higher temps
What is the difference between ventilation and perfusion?
ventilation is the mechanical flow of air/water from the environment to the inside of the organisms
perfusion is the physiological element of how air moves into and out of the blood
What organisms do evagination and invaginations occur in? their importance?
evaginations = gills of water-breathing animals invaginations = terrestrial animals, prevents drying out
How do flatworms breathe? positive and negative aspects?
use their whole body (skin) for diffusion of water
positives: large surface area
negatives: thickness (d) of skin
How do salamander breathe? positive and negative aspects?
mainly external gills but can use whole body if necessary
positive: thin external gills (d)
negative: smaller surface area than flatworms
What are the positive and negative aspects of diffusion in humans?
positive: large SA
negatives: thick, lacks directionality, delta p can change
to a worser condition
What are the advantages and disadvantages for water as a respiratory media?
advantages: less risk of evaporation
disadvantages: holds less O2, slower diffusion, high
density, high viscosity—need more
energy
What are the advantages and disadvantages for air as a respiratory media?
advantages: holds more O2, low density, low viscosity,
diffuse faster
disadvantages: higher risk of evaporation when breathing
What are opercula?
gill flaps of fish
How do fish breathe?
take water in through their mouth, water passes over/through gills to collect O2—uses countercurrent flow
What occurs in countercurrent exchange? advantages? how much O2 can it remove from the water?
flow of water and blood is opposite
advantage: At any point along the gill filament, the water is more highly oxygenated than the blood — allows for diffusion at all points
can remove 80-90% of water’s O2 content
What are spiracles?
holes in the exoskeleton that allow for the diffusion of air
What is the trachea of insects made of? what do they lead to?
made of chitin, lead to tracheoles
Difference between positive pressure breathing and negative pressure breathing?
positive pressure breathing is gulping air into the lungs and negative pressure breathing is when the air is pulled into the lungs vis muscular contractions
How do frogs breathe?
1) takes in air from the mouth and forces it down into the lungs
2) gas exchange
3) air is forced out when muscles in the body wall above the lungs contract and the lungs recoil elastically
How do birds breathe?
use countercurrent exchange system
use 9 pairs of air sacs
oxygenated and deoxygenated air do not mix in the lungs
air travels via parabronchi
air in, trachea, posterior sacs, lungs, anterior sacs, air out
Pathway of air in humans?
air enters via mouth and nose, throat (pharynx), larynx (voice box), bronchi, bronchioles, aveoli
How do the structure of the larger bronchi and smaller bronchi/bronchioles different?
lager bronchi do have muscle, the smaller bronchi/bronchioles have smooth muscle
What happens when you smoke?
paralyzes cilia in the bronchi and throat
What happens to the aveoli in pneumonia?
fluids and blood fills is, increases d and delta p, decreases SA
What happens to the aveoli in emphysema?
aveoli membranes break down, decreases SA
What happens to the aveoli in asthma?
constriction of bronchi
What is the pleura?
double layer of epithelial tissue with a slippery fluid to allow the lungs to move within the chest cavity
What muscles are activated when we exhale?
abdominal wall muscles and internal intercostal muscles
What is tidal volume? at rest?
volume of air entering and leaving the lungs during inhalation and exhalation
around 500 mL at rest
What is vital capacity?
maximum tidal volume of an individual
About 3,400 mL in females and 4,800 mL in males
What is residual capacity?
the amount of air that remains in the lungs after forceful exhalation
About 1,000 mL in females and 1,200 mL in males
What is the rate and depth of breathing controlled by?
interneurons in the medulla and pons
What acts as the primary stimulator of inhalations?
dorsal group of interneurons in the medulla
What signals breathing during physical exercise?
a ventral group of interneurons in the medulla sends signals for both inhalation and exhalation
How do the pons regulate breathing?
Two interneuron groups in the pons modulate the signals from the medulla so that breathing is gradual and controlled
Where are chemoreceptors located?
located centrally on the surface of the medulla, and peripherally in the carotid arteries (carotid bodies) and the aorta (aortic bodies)
What do the chemoreceptors in the medulla do?
detect pH changes in the cerebrospinal fluid
What is the effect of hemoglobin in the blood and plasma?
Combination with hemoglobin lowers the PO2 of the plasma and allows additional O2 molecules to diffuse into the blood
What percentages is O2 carried in the body by?
About 98.5% of the O2 in blood is carried by hemoglobin and about 1.5% is carried in solution in the blood plasma
What enzyme helps convert CO2 to carbonic acid?
carbonic anhydrase
What does carbonic acid disassociate into?
H+ and bicarbonate
What is the pH of blood?
7.4
