The cardiovascular system and its response to exercise

Aims of the seminar To recap on the previous session (the structure and function of the cardiovascular system. To identify the changes in heart rate during exercise. To identify and understand the changes in the respiratory system during exercise. To know cardiovascular adaptations during long and short periods of exercise.

The function of the circulatory system The circulatory system has three major function: Transport Moving things around the body in the blood stream such as oxygen and nutrients like glucose. Body temperature control Thermoregulation, moving blood near the skin cools down the body. That’s why you look redder when you exercise heavily. Protection Moving anti-bodies around the body fighting diseases and clotting cuts.

The structure of the heart Oxygenated blood has more oxygen and is found in the arteries (except in the pulmonary artery). Deoxygenated blood has less oxygen and is found in the veins (except in the pulmonary vein.)

Task one

The cardiovascular system: HEART Situated in the left-hand side of the chest Muscular pump whose purpose is to drive the blood into and through the arteries, to deliver it to the tissues and working muscles Considered as two separate pumps Two chambers on the right, and two chambers on the left side (the septum separates these chambers) What are they?

Strokes of the heart Heart rate per minute is how many time the heart beats in one minute. Stroke volume is the amount of blood pumped from the heart per beat. Cardiac output is the amount of blood pumped from the heart in one minute. Cardiac output = Stroke volume + Heart rate

Circuits of the body There are two circuits of the body you need to know: Systemic The main circuit of the body, it carries oxygenated blood around the body through arteries. It carries deoxygenated blood back to the heart and lungs through veins to be deoxygenated in the pulmonary system. Pulmonary Consists of the heart and lungs, deoxygenated from the heart to the lungs to be oxygenated. The oxygenated blood then goes back to the heart to be pumped around the body.

Changes in heart rate during exercise There is a anticipatory rise due to hormonal action. Then there is a sharp rise due to stimuli and hormonal response. The heart rate steadies off during constant maximal exercise (heart rate max)

Changes in the respiratory Tidal volume increases. Residual volume increases. Breathing rate and the volume of oxygen consumed is increased due to the onset of lactic acid.

Adaptations to the body over long periods of exercise. Increase in the number of capillaries. Increase in the efficiency of gaseous exchange. Lower resting heart rate.

Aerobic adaptations in the muscle during exercise Long aerobic exercise such as swimming or running can enlarge the slow twitch fibres allowing a greater potential for energy production.

Aerobic adaptations in the muscle during exercise The size and number of mitochondria increase. There is an increase in myoglobin within the muscle cell. The onset of fatigue is delayed because of the higher maximum oxygen uptake.

Anaerobic adaptations in the muscle during exercise Anaerobic activities such as sprinting and weightlifting can cause hypertrophy of the fast twitch muscle fibres.

Anaerobic adaptations in the muscle during exercise Increased stroke volume at rest and during exercise. Increased cardiac output. Decreased resting blood pressure. An increase in haemoglobin (helps carry oxygen along in the red blood cells.

You must include this in your assignment. Major muscles: triceps; biceps; quadriceps; hamstrings; deltoids; gluteus maximus; gastrocnemius; abdominals; obliques; pectorals; trapezius; erector spinae; classification; location Types of muscle: voluntary (skeletal); involuntary (smooth); heart (cardiac) Muscle movement: tendons; antagonistic pairs; types of movement (concentric, eccentric, isometric) Effects of exercise: short-term effects of exercise eg break down of muscle tissue; long-term effects of exercise eg hypertrophy

Next seminar Introducing the Digestive system including watching the third section form the DVD entitled ‘anatomy for beginners’.

Extended reading BTEC National diploma student guide (the complete revision).