Endocrine System- ReetaS14R Quizlet

Endocrine system

Consists of glands that control many of the body's activities by producing hormones.

Endocrine system relation to nervous system

The endocrine system works in conjunction with the nervous system, however it differs from the nervous system in that its chemical signals are slower-moving and longer-lasting.

Endocrine glands

Endocrine glands make chemicals called hormones, which are released into the bloodstream.

Hormones

Chemical substances act as messengers in the body.

target cells

cells that have receptors for a particular hormone

general effects/specific effects

Some hormones have general effects, acting on all of the cells in the body. For e.g. adrenaline - targets all the body. Other hormones have specific effects acting on certain organs, e.g. thyroid-stimulating hormone targets the thyroid.

circulatory system

Hormones are transported via the circulatory system, hence why all endocrine glands have blood vessels coming from them.

endocrine glands around the body

endocrine glands release hormones into the bloodstream. The hypothalamus, pituitary gland, and pineal gland are in your brain. The thyroid and parathyroid glands are in your neck. The thymus is between your lungs, the adrenals are on top of your kidneys, and the pancreas is behind your stomach.

Pituitary

master gland

Role ofThyroid

regulates metabolism

Pancreas

Pancreas produces Insulin & Glucagon: Both hormones regulate sugar (glucose) levels in the bloodstream.

Ovaries

Produces Oestrogen & Progesterone: Control development during puberty, prepares and maintains body during pregnancy and regulates the menstrual cycle.

Testes

testosterone, controls male development during puberty, body hair growth and a deepening of the voice.

Hypothalamus function

The most important function of hypothalamus is to link the nervous system and the endocrine system. It secretes (releases) hormones that act on the pituitary gland. the hypothalamus controls important aspects of the body such as body temperature, rate of metabolism and water content.

Fight or flight response

In situations of fear or stress both the nervous system and endocrine system have roles to play. This response is known as the 'fight or flight response'. The endocrine system releases hormones adrenaline and cortisol, which increase heart rate, breathing rate and blood pressure. Blood glucose levels also rise to provide muscles with the required energy for this response.

Homeostasis

The process of maintaining a constant internal environment is known as homeostasis (homeo means 'same' and stasis means 'sate'). Homeostasis involves receptors that are sensitive to a particular stimulus, and effectors, muscles or glands that have an effect on the same stimulus. This type of control is known as a feedback system.

Negative feedback

A primary mechanism of homeostasis, If the levels are too high or too low, feedback is sent to bring it back to normal.

Starting from the nervous system, outline the sequence of events by which the endocrine system increases body temperature.

Body temperature is also controlled by the nervous system and this is a more immediate response. When the hypothalamus detects a drop-in temperature, it sends nerve impulses to muscle groups around vital organs such as the heart and lungs. Small shaking movements extend to the large muscles of the arms and legs, and you begin to shiver. Shivering increases the activity of muscle cells, producing heat and raising body temperature. This is the body's way of creating warmth by using energy.

Explain what happens to your body when you get too cold

Muscles contract quickly and we shiver. Blood vessels leading to the skin capillaries become narrower - they contract - letting less blood flow through the skin and conserving heat in the body. The hairs on the skin also help to control body temperature. They rise when we are cold. The hairs trap a layer of hair above the skin, which helps to insulate the skin against heat loss.

Explain what happens to your body when you get too hot?

Sweat glands in the skin release more sweat. The sweat evaporates, removing heat energy from the skin. Blood vessels leading to the skin capillaries become wider - they dilate - allowing more blood to flow through the skin, and more heat to be lost.

What part of the brain detects a change in the temperature?

The hypothalamus is the part of the brain which monitors the body's temperature. It receives information from temperature-sensitive receptors in the skin and circulatory system.

How would shivering help maintain body temperature?

Muscles contract rapidly - we shiver. These contractions need energy from respiration, and some of this is released as heat.

What three functions in your body are regulated by hormones?

Growth, sleep and waking patterns and menstrual cycle (as well as metabolism).

Type 1 Diabetes

Hormones involved include glucagon and insulin, both produced by the pancreas. The pancreas produces glucagon and insulin.
- Increased thirst
- Increased urination
- Constant hunger
- Weight loss
- Blurred vision
- Constantly feeling tired
The causes of type 1 diabetes are not fully known. In most cases, the body's immune system attacks and destroys the part of the pancreas that produces insulin.