CONTROL OF BLOOD SUPPLY CIRCULATORY O2 AND CO2 TRANSPORT WARM UP AND COOL DOWN – EFFECTS ON VASCULAR SYSTEM

FIVE MECHANISMS HELP MAINTAIN VR DURING EXERCISE: VENOUS RETURN VR IS THE DEOXYGENATED BLOOD RETURNING TO THE HEART FIVE MECHANISMS HELP MAINTAIN VR DURING EXERCISE: POCKET VALVES SKELETAL MUSCLE PUMP RESPIRATORY PUMP SMOOTH MUSCLE GRAVITY

BLOOD POOLING INSUFFICIENT PRESSURE TO PUSH BLOOD BACK TOWARDS THE HEART CAUSES BLOOD POOLING (BLOOD SITS IN POCKET VALVES OF VEINS) ACTIVE COOL DOWN PREVENTS POOLING AFTER EXERCISE BY MAINTAINING THE MUSCLE AND RESPIRATORY PUMPS.

STARLING’S LAW OF THE HEART SV / Q IS DEPENDENT ON VR IF VR INCREASES, SV / Q INCREASES IF VR DECREASES, SV / Q DECREASES

REDISTRIBUTION OF Q AT REST 15 – 20% OF RESTING Q GOES TO MUSCLES 80-85% SUPPLIES BODY’S ORGANS (KIDNEYS, LIVER, STOMACH, INTESTINES)

REDISTRIBUTION OF Q EXERCISE 80-85% Q SUPPIED TO WORKING MUSCLES DECREASED % TO ORGANS BLOOD SUPPLY TO BRAIN MAINTAINED INCREASED BLOOD TO SKIN DURING LOW INTENSITY X – REDUCE BODY TEMP. REDISTRIBUTION OF Q – VASCULAR SHUNT SKELETAL MUSCLE ARTERIOLES AND PRE-CAPILLARY SPHINCTERS VASODILATE, INCREASE BLOOD TO WORKING MUSCLES ORGAN’S ARTERIOLES AND PRE-CAPILLARY SPHINTERS VASOCONSTRICT, DECREASING BLOOD FLOW TO ORGANS

VASOMOTOR CONTROL CENTRE VASOMOTOR CONTROL CENTRE (VCC) LOCATED IN MEDULLA OBLONGATA CHEMO AND BARORECEPTORS STIMULTATE VCC VCC STIMULATES SYMPATHETIC NS, WHICH CONTROLS BLOOD VESSEL LUMEN DIAMETER OF ORGANS AND MUSCLES

02 TRANSPORTATION 97% WITHIN PROTEIN HAEMOGLOBIN, PACKED WITH RBC’S, AS OXYHAEMOGLOBIN (Hb02) 3% WITHIN BLOOD PLASMA

C02 TRANSPORTATION 70% DISSOLVED IN WATER A CARBONIC ACID 23% CARBOAMINOHAEMOGLOBIN (HbCO2) 7% DISSOLVED IN PLASMA

WARM UP - VASCULAR GRADUAL INCREASE IN BLOOD FLOW / Q DUE TO VASCULAR SHUNT: VASOCONTRICTION OF ARTERIOLES / PRE-CAPILLARY SPHINCTERS TO ORGANS VASODILATION OF MUSCLE ARTERIOLES / PRE-CAPILLARY SPHINCTERS INCREASING BLOOD FLOW TO MUSCLES INCREASED BODY TEMP / MUSCLE TEMP: INCREASING ENZYME ACTIVITY REQUIRED FOR MUSCLE CONTRACTIONS DECREASES BLOOD VISCOSITY, IMPROVING BLOOD FLOW TO MUSCLES, INCREASING DISSOCIATION OF O2 FROM HAEMOGLOBIN DECREASED ONSET BLOOD LACTATE ACCUMULATION (OBLA)

COOL DOWN - VASCULAR KEEPS METABOLIC ACTIVITY ELEVATED, WHICH GRADUALLY DECREASES HR AND RESPIRATION MAINTAINS RESPIRATORY / MUSCLE PUMP WHICH: PREVENTS BLOOD POOLING MAINTAINS VR MAINTAINS BLOOD FLOW (SV / Q) - SUPPLYING O2 MAINTAINS BLOOD PRESSURE KEEPS CAPILLARIES DILATED TO FLUSH MUSCLES WITH OXYGENATED BLOOD WHICH: INCREASES THE REMOVAL OF BLOOD, MUSCLE LACTIC ACID AND CO2.

KEY WORDS SMOOTH MUSCLE VASODILATE VASOCONSTRICT VENODILATE VENOCONSTRICT PULMONARY SYSTEMIC POCKET VALVES VASCULAR SHUNT