Search Results

Angiotensin II - kidneys, adrenal glands and dehydration

By: HWC, Views: 6837

• Angiontensin II targets cells in the proximal convoluted tubule of the nephron. ■ The reabsorption of Na+ and Cl- ions sets up an osmotic gradient favoring the retention of water. • Decreases urine production and increases blood volume and pressure. • Angiontensin II targets zon...

Structures that affect circulation - arterioles and vasomotor responses and venous return

By: HWC, Views: 6747

■ Small arteries and arterioles determine SVR. • Blood pressure drops significantly as blood passes through arterioles. • Decreasing arteriole radius and decreased wall elasticity are the main reasons for increased SVR. ■ Small changes in arteriole radius can cause large changes in ...

Baroreceptor Reflex

By: HWC, Views: 6020

Baroreceptors located In the carotid sinus and the arch of the aorta respond to increases in blood pressure. Increased blood pressure stretches the carotid arteries and aorta causing the baroreceptors to increase their basal rate of action potential generation. Action potentials are conduct...

Heart sounds

By: HWC, Views: 6527

During a normal, healthy heartbeat, or what we call a cardiac cycle, the top two chambers of the heart, called the atria, contract simultaneously. Then, as they relax, the bottom two chambers, called the ventricles, contract. This explains what happens during a cardiac cycle, but what it doesn't ...

Stroke volume - contractility definition

By: HWC, Views: 6297

Contractility is the forcefulness of contraction of cardiac muscle. • Inotropic agents are substances that increase or decrease contractility (and stroke volume). • Positive inotropic agents increase contractility and will increase stroke volume and cardiac output. • Negative inotropi...

Forming urine ( influencing factors), Forming dilute urine & Forming concentrated urine

By: HWC, Views: 7120

• The amount of urine produced by the nephron depends on : • Body fluid volume. • Body fluid composition. • Dilute urine is formed when the body is normally hydrated. • The medullary osmotic gradient determines the osmolarity of the filtrate. • Filtrate osmolarity increase...

Cardiac Cycle (Part 2 of 4)

By: Administrator, Views: 9698

Prior to atrial systole, blood has been flowing passively from the atrium into the ventricle through the open AV valve. During atrial systole the atrium contracts and tops off the volume in the ventricle with only a small amount of blood. Atrial contraction is complete before the ventricle begins...

Medullary osmotic gradient - influencing factors

By: HWC, Views: 7018

▪ Maintenance of fluid volume and composition, despite changes in water input and output, is crucial to a healthy life. ▪ Regulation of blood's osmolarity, or solute concentration, is a function of the nephron. • Normal osmolarity is maintained by the ability of the nephron to alter uri...

Structures that affect circulation - heart and systolic/diastolic BP

By: HWC, Views: 6606

• Heart generates blood pressure. • Arterioles produce resistance thereby regulating blood flow to tissues. • Veins store blood; kidneys regulate blood volume; both affect venous return and cardiac output. ■ Contractions of the ventricles determine blood pressure, which drives th...