Chapter 6.2

Question 1

Describe the relation of the capillaries to the pulmonary arteries and pulmonary veins

Answer 1

Pulmonary arteries( originate from the right ventricle of the heart)

• > sends deoxygenated blood to the capillary to the alveoli
• > the carbon dioxide from this blood diffuses into the lungs

Pulmonary veins(left ventricle of the heart)
->oxygenated blood from the alveoli returns to the left atrium of the heart via pulmonary veins

Question 2

Describe the pressure gradient of deoxygenated blood at the alveoli? How this influences diffusion

Answer 2

• partial pressure of carbon dioxide is high
• partial pressure of oxygen is low
• so oxygen enters the blood
• > carbon dioxide leaves and enters the lungs

Question 3

How is heat regulated through the body surfaces?

Answer 3

• it has to do with vasodilation and vasoconstriction
• > vasodilate and a larger amount of thermal energy can be lost
• > vasoconstrict, less blood passes through and thermal energy is conserved

-also regulate through sweat glands or rapid muscle contraction(shivering)

Question 4

How does the lungs fight off potential invaders. Describe the different lines of defense that it has, starting off with the first one.

Answer 4

• first line of defense is within the nasal cavity
• > small hairs to help trap particular matter and infectious particles
• nasal cavities also contain lysozymes
• > lysozymes is able to attack the peptidoglycan walls of gram-positive bacteria
• internal airways are lined with mucus
• > traps matter and large invaders
• > underlying cilia then propel the mucus up the respiratory tract to the oral cavity where it can be expelled
• > this process is known as the mucociliary escalator
• macrophages can engulf and digest pathogens
• > signalling to the rest of the immune system that there is an invader
• mast cells have antibodies on the surface
• > when the right substance attaches
• > it releases inflammatory chemicals
• > these chemicals promote an immune response