Definitions ~

Negative Feedback Loop:

a cycle in which the last step in a sequence inhibits the first step in the sequence.

Positive Feedback Loop:

a cycle in which the last step in a sequence triggers the first step in the sequence.

Examples~

positive feedback loop:

-Child Birth

baby pushes against cervix, cervix stretch -> cervix stretch cause nerve impulses to the brain -> brain makes the pituitary release oxytocin -> oxytocin makes the uterus contract (in a cycle until baby is born)

or

[During labor]

oxytocin hormone when released causes the contractions to intensify and speed up -> increase in contraction = more oxytocin [continue until baby is born]

- Blood clots

vessel damage -> platelets cling and release chemicals to call more platelets at injured area -> platelets pile up and release chemicals -> clot is formed

-Milk Let down

baby latches on the nipple -> impulses go to the hypothalamus -> hypothalamus signals go to the posterior pituitary and releases oxytocin -> oxytocin releases into the bloodstream and stimulates milk ejection from the mammary gland -> milk is releases and baby feeds (cycle continues as the baby continue to suck)

Negative Feedback Loop: Normal Calcium Levels in Blood

What makes Blood Calcium Levels a negative feedback loop as the last step inhibits the first step in the sequence.

Definition:

Regulating the osmotic pressure in your body to maintain homeostasis.

Organs Involved:

Kidney

How this happens/Descriptions:

- Too little water

- Receptors in brain is triggered

- Pituitary releases more ADH

- Kidney releases more water

- Receptors in brain note the change in the blood (volume&concentration)

- Pituitary stops releasing ADH

- Blood keeps its concentration

- Too much water

- Pituitary secretes less ADH

- Kidney absorbs the water

- Receptors in brain note the change in the blood (volume&concentration)

- Pituitary starts releasing ADH

- Blood keeps its concentration

======================================================================

Definition:

Process of levelling blood-glucose levels to normal

-If the blood glucose level gets too high, then the pancreas releases insulin, which then activates the liver to convert the excess glucose to glycogen. Glycogen can be stored for future use.

-If the blood glucose gets too low, then the pancreas will limit the production of insulin, which makes the liver convert the stored glycogen into glucose.

-Pancreas makes insulin which opens up the cell membrane for glucose which is in the blood stream to go inside

-For homeostasis, insulin is the main hormone involved. Blood sugar regulation is the process by which the levels of blood sugar, primarily glucose, are maintained by the body. Glucose regulation in the body is a process of keeping the body in homeostasis.

-Insulin is secreted by the beta cells of the pancreas in response to high-blood sugar, although a low level of insulin is always secreted by the pancreas. After a meal, the amount of insulin secreted into the blood increases as the blood glucose rises.

Definition: Regulation of the concentration of calcium in blood.

Description:

Negative Feedback loop-A cycle in which the last step in a sequence inhibits the first step in the sequence

When calcium levels are too high, the thyroid releases calcitonin and increases the calcium deposition in bones. Which also causes a decrease of calcium levels in the uptake of the intestines and reabsorption from urine. Then calcium levels fall; when it gets too low the parathyroid releases PTH. This causes an increase of calcium levels from the bones and an increase calcium uptake in intestines and reabsorption from the urine. The calcium levels rise and the cycle repeats.

Diagram:

_{Function: The endocrine system is a complex group of glands that helps to control reproduction, metabolism, growth and development through substances called hormones.}

Glands and their Hormones:

-Posterior Pituitary: Oxytocin, Antidiuretic Hormone (ADH)

-Anterior Pituitary: Follicle-Stimulating Hormone (FSH), Luteinizing Hormone (LH), Adrenocortitropic Hormone (ACTH), Thyroid-Stimulating Hormone (TSH), Growth Hormone (GH), Prolactin (PRL)

-Thyroid: Thyroid Hormone (TH), Calcitonin

-Parathyroid: Parathyroid Hormone (PTH)

-Adrenal Gland: Epinephrine/Norepinephrine, Aldosterone, Cortisol

-Pancreas: Insulin, Glucagon

-Testes: Testosterone

-Ovaries: Estrogen, Progesterone

-Pineal Gland: Melatonin

-Thymus: Thymosin

-Kidney: Erytropoetin

Function of hormones:

_{- (ADH) a chemical that tells the kidneys how much water to conserve}

_{- Oxytocin cause contractions in the womb during child birth}

_{- Calcitonin helps regulate calcium and phosphate levels in the blood}

_{- Thyroid hormone are to absorb iodine}

_{- PTH brings the level of calcium back to normal}

_{- Aldosterone aid in the conservation of sodium, secretion of potassium, water retention and stabilize blood pressure}

_{- Epinephrine/Norepinephrine is the fight or flight response hormone}

_{- Cortisol influence, regulate or modulates any changes occurring in the body}

_{- Insulin takes glucose from the blood for energy}

_{- Glucagon raises the concentration of glucose in the bloodstream}

_{- testosterone plays a key role in the development of male reproductive tissues}

- Estrogen helps develop female secondary sexual characteristics

- Progesterone thickens the lining of the uterus every month

- Melatonin helps regulate other hormones and maintain the body's circadian rhythm

- Follicle-stimulating hormone are essential to pubertal development. Function of women's ovaries and men's testes

- Luteinizing hormone triggers ovulation and development of the corpus luteum

- Adrenocortitropic Hormone stimulates the release of cortisol

- TSH causes the thyroid gland to produce their hormones

- growth hormone helps the developments of bones

Endocrine distruptors are pretty self explanatory, they are  

- Chemicals that destroys our endocrine system. 

These distruptors can cause:

- Birth defects

- Cancerous tumours

- Other developmental disorders. 

Some of these distruptors are like lead, BPA, mercury, chlorine, etc.

Onset Puberty is usually the beginning stage of puberty, where girls usually start to develop breast. Usually onset puberty starts at the age of 10 until 14. But for some African-American girls, puberty would start earlier and longer. They start at the age of 9 until 14. For those who have start puberty, they would likely have symptoms of anxiety, depression, and would start have sexual behavior. For girls, after they start to develop breast, they would start to go to the next step of puberty which is growth of pubic hair and afterward growth of armpit hair. After the growth of hairs, onset menstruation is the next step to puberty but this usually happens later that the other physical changes. It could happen in around a year or two after the onset puberty. For boys, they usually start at the age of 12 until 16. For boys, their onset puberty would start by the enlargement of their testicles. This would begin at the age of 11. It would also enlarge by it size. Next, they would start to have a change of voice, where their voice becomes deeper and their muscles would increase in size. Last stage of puberty for boys would be having facial hair

How both of it relates:

Early onset puberty happens when our endocrine system is not fuctioning properly or is distrupted. In an early onset puberty, scientist had found out that 

- The endocrine distruptor is a chemical that mimics the funtion of natural hormones. -- Researches are most concerced with estrogen 

- Chemicals like BPA mimics estrogen. It was meant for a medical estrogen but nowadays people use it for plastic, paper, receipts, and in other compounds. 

- It also distrupts male's puberty by delaying their puberty

- It relates because the endocrine distruptor is what triggers the early onset puberty.

Fish Population:

In Canada, a biologist ran some experiment on fishes in the Canadian rivers. It was discovered that male fishes starts to develop female hormone due to the birth pills that people took and the birth pills did not get digested in the people's body. When someone takes the pills and the pills does not get digested, when they excrete the undigested pills out, the waste may not be completely broken down in sewage system

Insulin is required for glucose to be broken down and processed.

NEGATIVE FEEDBACK = a cycle in which the last step in a sequence inhibits the first step in the sequence.

POSITIVE FEEDBACK = a cycle in which the last step in a sequence triggers the first step in the sequence.

Similarities the nervous and endocrine system

- regulate PHYSIOLOGICAL ACTIVITIES

- maintain HOMEOSTASIS

- use FEEDBACK LOOPS

Differences

*NERVOUS SYSTEM

- Brain, spine, nerves.

- Signal is delivered (via. neuro transmitter)

- Fast response

- Short duration

*ENDOCRINE SYSTEM

- gland and hormones

-Hormones deliver signals (via. blood stream)

-Slow response

-Longer duration

having a higher osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid.

Isotonic: equilibrium

Hypotonic: k

having a lower osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid.Osmoregulation: Sally, Tiffany, and Ian