Chemistry Term 2

What is negative feedback loop?

A negative feedback loop is when the body reverses a change to bring the body back to normal

What is positive feedbackloop?

Amplification of bodily functions to bring the body to a specific outcome.

What is the homeostasis model?

It begins with a stimulus,then sensors detect this change and send signals to the control center. Then the control center or a specific gland chooses an appropriate action based on the signal. After effectors carry out the action followed by the target being reached.

Why does homeostasis matter?

Homeostasis matters because it is essential in allowing our cells to thrive and the body in general. Also enzymes are sensitive, meaning small fluctuations in temperature can denature enzymes.

What is the endocrine system?

The endocrine system is a network of glands that produce and release hormones — chemical messengers that travel through the bloodstream to target organs.

What is the hypothamulus?

found in the brain and is the control center and it monitors body conditions by controlling hormone release,

What is the pituitary gland?

ound in the brain and responsible for growth hormone, and is called “the master” gland because it controls many other glands,

What is the pancreas?

Gland that secrets glucagon and insulin.

What is a hormone pathway?

A hormone pathway is the path a hormone undergoes to reach a target organ through the bloodstream.

What is a target organ?

A target organ is an organ or tissue that contains receptors for a specific hormone and responds to that hormone. 

What is the proccess of the endocrine system?

Something triggers the body (stimuli), then a gland detects this change and produces a hormone, after the hormone is released in the bloodstream where the target organ only responds because only that organ has the right receptor. After the target organ respons to the hormone which changes its behaviour. Finally after the body detects the balance has been restored, it signals to stop producing the hormone.

What happens when glucose levels is too high or low?

• It must stay withing 4-8 mmol/L and if too low it starves cells and too high causes damage organs and blood vessels.

What is glucagon, glycogen and insulin?

Glucagon: Low

Glycogen: Excess glucose is turned into this and turned back

Insulin: High

What happens to the body when fasting?

• Stimulus:

  Blood glucose level falls

  ↓

  Receptors/Control Centre:

  Pancreas detects low blood glucose

  ↓

  Effector:

  Pancreas releases glucagon

  ↓

  Response:

  Liver breaks down glycogen into glucose

  and releases glucose into the bloodstream

  ↓

  Blood glucose level rises

  ↓

  Homeostasis restored

What is type 1 and type 2 diabetes?

1) Beta cells that produc insulin is mistakenly attacked which leads to dangerously high glucose levels becase they cannot enter cells.

2) It becomes resistant to insulin because the receptors don’t respond to inslun’s signa

What happens when temperature is too high or too low in the body?

 It doesn’t usually harm enzymes, just brings them away from optimal activity. Above 40 degrees they denature, too cold they are slowed down.

What happes when your body is too hot or too cold:

• The body starts to sweat and vasodilates which allow heat to radiate outward.  When cold your body starts to shiver to generate metabolic heat and the blood Vasoconstrict to prevent the heat escaping.

What is Mode of Transmission?

• How pathogens spread.

What are the two types of immunity?

innate; natural defence and adaptive immunity which is immunity developed after exposure to a pathogen

What are the 3 lines of defence and which is adaptive?

• The 3 lines of defence include the following: the first being physical barriers such as skin, tears, mucus, etc. The second barrier is inflammation, fever and phagocytes whereas the third consists of antibodies, T and B lymphocytes.

What is an antigen?

It is the molecule on a pathogen which triggers and immune response.

What is an antibody?

•  It is produced by B cells which attaches to antigens to destroy pathogens.

What is the lymphatic system?

• Lympahtic system is a collection of vessels and organs which transport immune cells, remove excess fluid from tissues and produce white blood cells.

What are the types of a white blood cell?

White blood cells is apart of the immune system. There are 3 types, neutrophil which quickly attacks and kills pathogen, macrophage which engulfs and digests pathogens and memory cells.

What is a lymphocyte?

• Lymphocytes iis a type of white blood cell by recognising specific antigens and carrying out targeted immune response.

Give 2 examples of an illegal drug?

Erythropoietin is produced in the kidney naturally which triggers the production of red blood cells but athletes get this artifically so they have more oxygen in blood.  The risk is heart attack and stroke and it is harder to pump thicker blood.

Another is anabolic steroids whcih mimics testosterone which is used to build strength and increase protein synthesis. This risk liver damage.