Chapter 42 Circulation and Gas Exchange

O2 and CO2 must dissolve in water before they can pass through a membrane so all respiratory membranes must be kept moist Diffusion is a slow process 1 sec over 1 um but 1000 seconds (over 16 minutes) over 1 mm

Open circulatory system- hemolymph- sinuses-arthropods respiratory pigment hemocyanin is not contain in cells and is very diffuse in the hemolymph

Reptilian heart has a partial septum in the ventricle

Pulmonary Aortic Tricuspid Valve Bicuspid or Mitral Valve

Bundle of His Purkinje fibers

Diastole- atria contract and ventricles relax and fill with blood, blood washes back in the arteries and closes the semilunar valves and produces the lower diastolic pressure Systole- ventricles contract forcing blood into arteries and a pulse and higher pressure called systolic pressure and slapping the atrioventricular valves shut Heart murmur- a defect in a valve that allows backflow mitral valve prolapse

Slide # 32 Comparison of vein and artery

Muscular constriction of arterioles and precapillary sphincters controls the flow of blood through capillaries Figure 23.11 1 Sphincters relaxed Capillaries Arteriole Venule Precapillary sphincters 2 Sphincters contracted Arteriole Venule Thoroughfare channel Thoroughfare channel

High hydrostatic pressure due to blood pressure in the smaller diameter capillaries on the arteriole end; low osmotic pressure pulling water in because the blood still has all its water Lower hydrostatic pressure due larger dia. vessels and less blood volume; higher osmotic pulling water in lower conc. of water vs. dissolved substances

Arteriole end of a capillary Venous end of a capillary

Slide # 31

Slide # 28

to cells that have tissue factor ->thromboplastin

Slide # 29 Blood clot Crenated red blood cell

4-6 liters of whole blood in average adult; 45% is cellular elements Ischemia-insufficient blood flow to portion of the heart that can result in angina pectoralis and death of a section of heart tissue Stroke-death of nervous tissue in the brain due to blockage of arteries Thrombus-stationary clot; embolus-moving clot Pulmonary embolism-most common place Atherosclerosis-fatty plaques attach to the artery walls Arteriosclerosis-plaques become hardened by calcium Aneurism-an enlarged weakened area of an artery Stenosis-the partial blockage of an artery

Normal stenosis with Plaque

Lymph is returned to the circulatory system through the subclavian veins using pressure changes in the thoracic cavity to pull the lymph into the blood stream.

edema-swelling caused by excess fluid loss from the capillaries can be caused by hypertension or capillary damage pulmonary embolism-most common place for an embolism to lodge

O2 does not dissolve in water very well Water has lower concentrations of O2 and it is also more dense; thus fish must use more energy in respiration but they do not have a problem with their respiratory membranes remaining moist so they can have more surface area.

Counter-current exchange

membranes around the lungs and lining the thoracic cavity are the pleural membranes; an infection is called pleurisy an infection of the larynx is called laryngitis

Slide 182 Nasal Septum Capillaries under the mucosa layer Mucus membranes moisten and warm the air

Slide # 185 Trachea

Slide # 186 Trachea epithelial lining

Slide # 189 Lung Bronchiole

Slide #191 Lung Alveoli

Slide # 193 Alveolar Macrophages

Lung Interalveolar Septum Slide # 194 Lung Interalveolar Septum Interalveolar septum Type II cell secretes surfactant Note thickness of cells between the air and the blood vessel Air spaces inside alveoli

The vagus nerve is a cranial nerve that has fibers connecting to both the diaphragm and the sinoatrial node to either slow or speed up both breathing and heart rate

CO2 Transport 7% in solution in blood plasma 23% binds to amino groups of hemoglobin 70% transported in the blood in the form of bicarbonate ions and H+

Diving mammals can stay submerged so long because they: have a higher blood volume have more hemoglobin and more erythrocytes/ml. of blood have more myoglobin in their muscle tissues only circulate blood to essential tissues during dives