25 terms

Homeostasis

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Homeostasis
(staying in balance)
term that is used to both describe the survival of organisms in an ecosystem and to describe the successful survival of cells inside of an organism.
Organisms and populations
maintain homeostasis in an environment when they have a steady level of births and deaths.

It is similar to the idea of equilibrium.
Internal workings of an organism
homeostasis describes an environment that supports the survival of cells.
All body systems work together maintain homeostasis inside of your body.
the nervous system and hormones are responsible for this.
Some of the other internal conditions that are controlled.
- Carbon dioxide

- Body temperature

- Water content
Carbon Dioxide
Carbon dioxide is a waste product of respiration.

It travels in the bloodstream from cells to the lungs, where it leaves the body when we exhale.
...
Carbon dioxide forms an acidic solution when it dissolves in water.

Carbon dioxide levels must be controlled to avoid the blood becoming too acidic or too alkaline.
Homoeothermic organism =
regulate your own body temperature (warm blooded).
Body Temperature
This is controlled to maintain the temperature at which enzymes work best, which is 37 °C.

Body temperature can be controlled by:
• sweating

• shivering

• altering blood flow to the skin.
Extremes of body temperature are dangerous because:
Low temperatures can cause hypothermia and death if untreated

High temperatures can cause hyperthermia, dehydration, heat stroke and death if untreated.
Body Temperature Control Mechanisms
The body's temperature is monitored by a part of the brain called the hypothalamus. If you are too hot or too cold, it sends nerve impulses to the skin.
Heat can be gained by
- respiration

- shivering

- exercise or

- reducing the blood flow to the skin.

Clothing also helps to retain heat.
If we get too hot, heat can be lost by reducing the blood flow to the skin or by sweating.
Sweating increases heat loss by evaporation.
Negative Feedback Mechanism
The body's internal environment is kept almost constant by:
- causing cooling if it gets too hot

- warming if it gets too cold.
Your nervous and endocrine systems
also contract the blood vessels of your circulatory system to keep blood in the core of your body and not the extremities (like fingers).
Water Content
This is controlled to protect cells by stopping too much water from entering or leaving them.

Water content can be controlled by altering water loss from the:
• lungs when we exhale

• skin by sweating

• body, in urine produced by the kidneys.
Hormones
Hormones are chemicals secreted by glands in the body.

Different hormones affect different target organs.
The bloodstream transports hormones from the glands to the target organs.
Bodily reactions to hormones are usually slower and longer lasting than nervous reactions.

The pancreas produces the hormone insulin.
Blood Sugar Levels
Glucose is a sugar needed by cells for respiration.

It is important that the concentration of glucose in the blood is maintained at a constant level.
Insulin, a hormone secreted by the pancreas, controls blood sugar levels in the body.
It travels from the pancreas to the liver in the bloodstream.

As with other responses controlled by hormones, the response is slower but longer lasting than if it had been controlled by the nervous system.
Glucose vs Glycogen
There are many types of sugars namely:
- Monosaccharide = Glucose
- Disaccharide
- Polysaccharide. = Glycogen

Glycogen is a more complex sugar than glucose.

When many glucose molecules bind altogether along with
oxygen glycogen can most likely be formed as an end result.
Diabetes
Diabetes is a disorder in which the blood glucose levels remain too high.

There are three types of diabetes:
- Type 1: which usually develops during childhood

- Type 2: which usually develops in later life

- Type 3: Gestational (due to pregnancy)
Type 1
Caused by a lack of insulin, the hormone which controls the level of glucose in the blood.

The pancreas produces much too little insulin and in some cases, no insulin at all.

Type 1 diabetes can be controlled by:
- diet: avoiding too much sugary foods and carbohydrates in the diet.

- injection: of insulin usually into the subcutaneous fat.
Injecting insulin will make the liver remove excess glucose from the digested food.

In Type 1 diabetes, the level of physical activity and diet affect the amount of insulin required.
Type 2
Caused by a person becoming resistant to insulin.

Obese people (BMI > 30) run the risk of developing type 2 diabetes.

The pancreas doesn't make enough insulin or the person has become resistant to insulin so the body doesn't even respond appropriately to any insulin present, and both will cause the blood sugar level to rise.

Type 2 diabetes can be controlled by:
- diet: eating a healthy balanced die
- physical activity: regular eating, regular exercise and losing weight if necessary.

Some Type 2 diabetics take insulin to help control this diabetic condition.
Homeostasis
(staying in balance)
term that is used to both describe the survival of organisms in an ecosystem and to describe the successful survival of cells inside of an organism.