Unit 9: Human Regulation and Reproduction
Homeostatic control of body systems
Introduction
Homeostasis is a term that was first defined by a French physiologist named Claude Bernard in 1965.
Homeostasis means maintaining a constant internal environment. It is a self-regulating process that
allows the different biological systems of the body to maintain stability while adjusting to the
changing external conditions.
Task 1
Temperature
The normal body temperature is known as being 37°C. The hypothalamus is responsible for the
internal body temperature. This is because, the skin contains temperature receptors that detect the
changes in the external temperature leading to neurons to transmit information as nerve impulses to
the thermoregulatory centre in the hypothalamus found in the brain. Additionally, the hypothalamus
also has receptor cells that detect changes in the temperature of the blood flowing through the
brain.
Depending on the temperature of the body whether it is lower or higher than it normally should be,
the hypothalamus sends electrical impulses to effectors, which are mainly found in the skin. When
the temperature is lower than it should be, the hypothalamus sends nerve impulses to the effectors,
skin, and muscles for different mechanisms to take place that would allow the temperature to return
to normal. An example of a mechanism is shivering as the repeated skeletal muscle contractions
allow heat to be produced. Another mechanism is vasoconstriction, which takes place in the blood
vessels that supply skin capillaries with blood, and it allows the blood flow near the surface of the
skin to be reduced leading to heat loss to be prevented. Erector muscles in hair follicles to contract
causing hairs to stand on end is another mechanism as it allows warm air next to the skin to be
trapped. Lastly, another mechanism for the temperature to return to normal is sweat glands to stop
secreting sweat which allows the heat to remain in the body.
When the temperature is higher than it should be, the hypothalamus sends nerve impulses to the
effectors, skin, and muscles for different mechanisms to take place that would allow the temperature
to return to normal. An example of the mechanism is shivering to be stopped due to the repeated
skeletal muscle contractions creating too much heat. Another mechanism is vasodilation, which
causes blood flow near the surface of the skin to allows the heat loss to increase. Erector muscles in
hair follicles to relax is another mechanism as it releases any warm air trapped next to the skin.
Lastly, another mechanism for the temperature to return to normal is sweat gland to start secreting
sweat that would eventually evaporate from the surface of the skin allowing heat energy to be
removed.
Once the blood temperature would return to normal, the processes that would be carried out by the
body.
Blood glucose levels
The normal blood glucose level is known as being between 4–6 mmol/L. The glucagon and insulin
hormones are responsible for the blood glucose level. These are secreted by beta and alpha cells in
the Islets of Langerhans, which are scattered throughout the pancreas. Glucagon is released to stop
blood sugar levels dropping too low whereas insulin is released to stop blood sugar levels rising too
Homeostatic control of body systems
Introduction
Homeostasis is a term that was first defined by a French physiologist named Claude Bernard in 1965.
Homeostasis means maintaining a constant internal environment. It is a self-regulating process that
allows the different biological systems of the body to maintain stability while adjusting to the
changing external conditions.
Task 1
Temperature
The normal body temperature is known as being 37°C. The hypothalamus is responsible for the
internal body temperature. This is because, the skin contains temperature receptors that detect the
changes in the external temperature leading to neurons to transmit information as nerve impulses to
the thermoregulatory centre in the hypothalamus found in the brain. Additionally, the hypothalamus
also has receptor cells that detect changes in the temperature of the blood flowing through the
brain.
Depending on the temperature of the body whether it is lower or higher than it normally should be,
the hypothalamus sends electrical impulses to effectors, which are mainly found in the skin. When
the temperature is lower than it should be, the hypothalamus sends nerve impulses to the effectors,
skin, and muscles for different mechanisms to take place that would allow the temperature to return
to normal. An example of a mechanism is shivering as the repeated skeletal muscle contractions
allow heat to be produced. Another mechanism is vasoconstriction, which takes place in the blood
vessels that supply skin capillaries with blood, and it allows the blood flow near the surface of the
skin to be reduced leading to heat loss to be prevented. Erector muscles in hair follicles to contract
causing hairs to stand on end is another mechanism as it allows warm air next to the skin to be
trapped. Lastly, another mechanism for the temperature to return to normal is sweat glands to stop
secreting sweat which allows the heat to remain in the body.
When the temperature is higher than it should be, the hypothalamus sends nerve impulses to the
effectors, skin, and muscles for different mechanisms to take place that would allow the temperature
to return to normal. An example of the mechanism is shivering to be stopped due to the repeated
skeletal muscle contractions creating too much heat. Another mechanism is vasodilation, which
causes blood flow near the surface of the skin to allows the heat loss to increase. Erector muscles in
hair follicles to relax is another mechanism as it releases any warm air trapped next to the skin.
Lastly, another mechanism for the temperature to return to normal is sweat gland to start secreting
sweat that would eventually evaporate from the surface of the skin allowing heat energy to be
removed.
Once the blood temperature would return to normal, the processes that would be carried out by the
body.
Blood glucose levels
The normal blood glucose level is known as being between 4–6 mmol/L. The glucagon and insulin
hormones are responsible for the blood glucose level. These are secreted by beta and alpha cells in
the Islets of Langerhans, which are scattered throughout the pancreas. Glucagon is released to stop
blood sugar levels dropping too low whereas insulin is released to stop blood sugar levels rising too
