It is now thought that the atmosphere of the primitive Earth was composed largely of carbon dioxide, nitrogen, and water vapor. The composition of certain iron-containing minerals suggests that the carbon dioxide began to be replaced by oxygen about 2 billion years ago.   Which of the following is the best explanation for the change in atmospheric composition?

#Question id: 11026

#Unit 7. System Physiology – Animal

Listed below are the hydrostatic and oncotic pressures and filtration rate across a muscle capillary wall:

Capillary hydrostatic pressure (Pc) = 25 mm Hg

Plasma colloid osmotic pressure (Πp) = 25 mm Hg

Interstitial colloid osmotic pressure (ΠI) = 10 mm Hg

Interstitial hydrostatic pressure (PI) = −5 mm Hg

Capillary filtration rate = 150 ml/min

What is the capillary filtration coefficient?

#Question id: 11025

#Unit 7. System Physiology – Animal

Listed below are the hydrostatic and oncotic pressures within a microcirculatory bed:

Plasma colloid osmotic pressure = 25 mm Hg

Capillary hydrostatic pressure = 25 mm Hg

Venous hydrostatic pressure = 5 mm Hg

Arterial pressure = 80 mm Hg

Interstitial fluid hydrostatic pressure = −5 mm Hg

Interstitial colloid osmotic pressure = 10 mm Hg

Capillary filtration coefficient = 10 ml/min/mm Hg

What is the rate of net fluid movement across the capillary wall?

#Question id: 11024

#Unit 7. System Physiology – Animal

A 55-year-old man has been diagnosed with Stokes-Adams syndrome. Two minutes after the syndrome starts to cause active blockade of the cardiac impulse, which of the following is the pacemaker of the heart?

#Question id: 11022

#Unit 7. System Physiology – Animal

A 55-year-old man had the following EKG recorded at his doctor’s office during a routine physical examination.

What is his diagnosis?

#Question id: 11014

#Unit 7. System Physiology – Animal

What is the normal QT interval?

#Question id: 11013

#Unit 7. System Physiology – Animal

What is the heart rate in the following EKG?