BRAINCAKEAdditional Responses
During exercise, raising the heart rate is only part of the body's response. Several other changes happen together, so that respiring muscles get enough oxygen and glucose and waste products are removed.
Stroke volume increases. More blood returns to the heart, so the ventricles fill more fully and are stretched more. Stretched cardiac muscle contracts more forcefully, and sympathetic impulses and adrenaline also strengthen contraction.
Blood is redistributed. Arterioles supplying skeletal muscles dilate (vasodilation), because the smooth muscle in their walls relaxes. Arterioles supplying the gut and kidneys constrict (vasoconstriction). Blood flow to the brain is kept constant.
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Key terms in this lesson
- chemoreceptor
- A receptor that detects the chemical composition of the blood, such as carbon dioxide concentration or pH.
- vasodilation
- Widening of a blood vessel, which increases blood flow through it.
- vasoconstriction
- Narrowing of a blood vessel, which decreases blood flow through it.
More in Homeostasis
- Nervous Control of the Heart
- Baroreceptors
- Chemoreceptors
- Hormonal Control of the Heart
- Protein Homeostasis in the Liver
- Osmoregulation
- Osmoregulation in Mammals
- Structure and Function of the Kidney
All 41 lessons in Homeostasis · All Edexcel A-level Biology topics