Heart Rate
The heart has two nervous systems that operates it- the sympathetic and the parasympathetic system. You could say that these systems work like an accelerator and a brake on the heart. The sympathetic system is active when the body is undergoing muscular work, fear or stress. It causes each heartbeat to increase in strength as well as an increase in heart rate. The parasympathetic system has an opposite effect; it calms the heart output and is active during resting.
Breathing Rate
When breathing rate increases because of excess carbon dioxide being produced, or decreases because of gasping, laughing or aftermath of exercise, homeostatic processes work together to regain the normal rate. Chemoreceptors, found in the brain are able to detect these changes in the ventilation rate and send this information for processing. The effectors are then sent information to make the change necessary to regulate breathing. In this case, these would be respiratory muscles in the diaphragm which causes relaxation and exertion and regulates the breathing to rate to regain normality.
Body temperature
Humans can survive both hot and cold regions; this is due to our thermo-regulatory homeostatic processes, our use of intelligence and the fact that out body temperature on varies rarely.
An adult’s body core temperature is 37ºC. Temperature detectors in the skin and internal organs monitor this and send messages to the hypothalamus in the brain to take appropriate action depending on whether it rises or falls.
Heat is lost through four main processes and these are;
- Radiation- which is like diffusion but of heat temperature
- Convection- when you warm up the layer of air net to you and is moved upwards to be replaced by cooler air
- Conduction- when you are warming up anything that you are in contact with, such as clothes.
- Evaporation- which is when liquid is converted into water vapour.
When the thermoreceptors detect that the body temperature is lower than normal, the heat gain centre inhibits the activity of the heat loss centre and sends impulses to the skin, hair erector muscles, and sweat glands to decrease heat loss and increase heat production.
Heat is produced as a result of metabolic reactions within the body. Homeostatic controls are needed to maintain the balance of heat production by metabolism and heat loss by the body via the skin and respiration. If there is a variation in temperature, the cardiovascular, endocrine and nervous system will then all work together to regain the balance. The receptors that detect these changes are situated in the hypothalamus, in the brain. The skin also has temperature receptors
When the thermoreceptors detect a higher temperature, then the heat gain centre activity that is inhibited by the heat loss centre. The hair erector muscles relax and so flatten the hair on the skin which nurses heat loss when the temperature is too high. The sweat glands only produce sweat when the body needs to loose heat. The sweat evaporates from the skin surface which assists in cooling the skin and nursing heat loss.
Blood Glucose Levels
The average amount of an adult’s blood glucose levels is normally between 4-7 mmol/l. Glucose is produced when carbohydrates are broken down by digestive enzymes. It is important energy source for the body and levels of glucose circulating around the body, in the blood need to be maintained at a constant level to ensure that the body works effectively and efficiently. However there are times when glucose levels changes due to normal daily activities, such as blood glucose levels rising after eating and falling after exercise. To try and minimise the extent of the blood glucose levels rising and falling, the pancreas produces two hormones which work opposite towards each other. These hormones are insulin, which reduces the blood glucose levels and glycogen, which increases the blood glucose levels. The pancreas closely monitors the glucose levels and the hormone which is released, depends on the increase or decrease of the blood glucose levels.
