Human Physiology Unit Seven Objective Twelve

Blood Volume and Its Control Blood volume is the amount of extracellular water found in the blood Increasing blood volume would increase EDV and therefore stroke volume Decreasing blood volume would decrease EDV and therefore stroke volume

Blood Volume and Its Control Blood volume can be regulated by ADH and aldosterone ADH (antidiuretic hormone) promotes thirst and the retention of water

Blood Volume and Its Control Increased blood volume Adrenal cortex  Aldosterone salt retention (water retention) Increased blood volume Aldosterone promotes salt retention, which will lead to water retention

Human Physiology Unit Seven Objective Thirteen

Definitions Blood pressure - the pressure exerted on the vessels of the circulatory system Systolic pressure - pressure exerted on the arteries during systole Diastolic pressure - pressure exerted on the arteries during diastole Pulse pressure - systolic pressure minus the diastolic pressure

Definitions Mean arterial pressure - the diastolic pressure plus one third the pulse pressure Blood pressure decreases as blood moves farther away from the heart. Therefore arteries are under the highest pressures, while capillaries and veins are under little or no pressure

Human Physiology Unit Seven Objective Fourteen

Poiseuille’s Law Pr4() L(8) Blood flow = Vessel length and blood viscosity do not change significantly, therefore the most important variable in changing blood flow is vessel radius

Human Physiology Unit Seven Objective Fifteen

Fluid Exchange Between Capillaries and Tissues

Human Physiology Unit Seven Objective Sixteen

Edema The excessive accumulation of fluid in the interstitial spaces of the tissues This condition can be temporary or chronic, depending upon its cause

Edema Five causes of edema - * Hypertension * Plasma colloid leakage * Myxedema * Decrease in plasma proteins * Obstruction of lymphatic vessels

Human Physiology Unit Seven Objective Seventeen

Blood Pressure Regulation Through Resistance Changes Angiotensin II - compound produced in the blood during times of low blood volume or pressure This is an example of extrinsic control

Blood Pressure Regulation Through Resistance Changes Sympathetic innervation - causes vasoconstriction and increases cardiac output Parasympathetic innervation - causes limited vasodilation and decreases cardiac output These are examples of extrinsic control

Blood Pressure Regulation Through Resistance Changes Myogenic action - direct responses of vascular smooth muscle in response to changes in pressure Metabolic changes - decreases in oxygen or pH, and increases in carbon dioxide lead to localized vasodilation These are examples of intrinsic control

Human Physiology Unit Seven Objective Eighteen

The Baroreceptor Reflex Integrating Center Sensor Effectors Stimulus Response

The Baroreceptor Reflex

Human Physiology Unit Seven Objectives Nineteen through Twenty Two

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