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Define the term “endocrine gland”.

A group of specialised cells which produce hormones and secrete them into the blood.


Define the term “exocrine gland”.

A group of specialised cells which produce enzymes and release them via a duct into the duodenum.


Define the term “hormone”.

Chemical messengers which travel around the body in the blood stream.


Define the term “target tissue”.

Specific cells which hormones act on to stimulate a response.


List 7 endocrine glands, the hormone they secrete and the general role of each hormone.

1) Pituitary gland - brain - produces growth hormone, adh and gonadotrophins which control growth of ovaries and testes.
2) Thyroid - throat - produces thyroxine, controls metabolism by controlling the rate glucose is used up in respiration, and promotes growth.
3) Adrenal gland - top of the kidneys - produces adrenaline, raises blood-glucose conc.
4) Testis - testicles - testosterone, controls sperm production and secondary sexual characteristics.
5) Pineal - brain - produces melatonin which affects reproductive development and daily cycles.
5) Thymus - chest - produces thymosin, promotes production and maturation of WBC.
6) Pancreas - Midriff - produces insulin, converts excess glucose to glycogen, lowering blood-glucose conc.
7) Ovary - produces oestrogen, controls ovulation and secondary sexual characteristics; progesterone prepares uterus lining for receiving an embryo.


Describe how hormonal communication occurs.

- Hormones are secreted directly into the blood when a gland is stimulated.
- Once secreted, hormones travels around the body in the blood plasma.
- Hormones diffuse out of the blood and bind to receptors specific to that hormone, found on the target cells.
- Once bound to their receptors, the hormones stimulate the target cells to produce a response.


State the location of the adrenal glands in the body and describe their structure.

- Located on top of the kidneys.
- Two distinct parts; adrenal cortex and adrenal medulla.
- Adrenal cortex: the outer region of the glands. Produces hormones that are vital to life e.g. cortisol and aldosterone.
- Adrenal medulla: the inner region of the glands, produces non-essential hormones such as adrenaline which helps the body react to stress.


Describe the role of the adrenal cortex and the functions of the hormones produced.

Production of hormones from adrenal cortex is controlled by hormones released from the pituitary gland.

- includes cortisol, which helps regulate metabolism by controlling conversion of fats, proteins and carbs to energy. Regulates blood pressure in response to stress.

- Also includes corticosterone, regulates immune response and inflammatory reactions.


Describe the role of the adrenal cortex and the functions of the hormones produced.

- Aldosterone, controls blood pressure by maintaining balance of salt/water concentrations. Triggered by signals from the kidney.


Describe the role of the adrenal cortex and the functions of the hormones produced.

- Small amounts of male and female sex hormones. Important for women after the menopause.


Describe the role of the adrenal medulla and the functions of the hormones produced.

Hormones of the adrenal medulla are released when the sympathetic nervous system is stimulated - occurs when under stress.

- Adrenaline, increases heart rate sending blood quickly to the muscles and brain. Rapidly raises blood glucose concentration levels by converting glycogen to glucose.

- Noradrenaline, works with adrenaline in response to stress, increases heart rate, widening pupils, widening of air passages in the lungs, narrowing blood vessels in non-essential organs to raise the blood pressure.


Define the term “histology”.

Histology is the microscopic study of the structure of biological tissues.


Describe the roles of the pancreas.

Functions as exocrine gland and exocrine gland:
- Exocrine, produces enzymes and releases via a duct into the duodenum.
- Endocrine, produces hormones and released them into the blood.


What is the pancreas's function as an exocrine gland?

- Most of the pancreas is exocrine glandular tissue.
- Responsible for producing digestive enzymes and pancreatic juice (an alkaline fluid).
- Enzymes and juice are secreted into ducts which lead to the pancreatic duct, from here they are released into the duodenum (the top part of the small intestine).
- Amylase, protease and lipase are produced.


What is the pancreas's function as an endocrine gland?

- There are islets of langerhans in the exocrine tissue which contain alpha and beta cells.
- Alpha cells produce glucagon, beta cells produce insulin.


Draw a diagram of a pancreas section, label it and annotate with the functions of the structures labeled.

Two main structures:
- Islets of Langerhans; large spherical structure, endocrine tissue, produce and secrete hormones (contains alpha and beta cells).

- Pancreatic acini; small berry-like clusters, exocrine tissue, produce and secrete digestive enzymes.


Identify the components of the pancreas in a photomicrograph of a stained section.

Dark pink surroundings are the pancreatic acini (the exocrine tissue) and the spherical, white-blue blobs are the islets of Langerhans (endocrine tissue).
(see pp.387)


Define the term “α-cell”.

Alpha cell - present in the islets of Langerhans (endocrine tissue), they produce and secrete glucagon, which stimulates the conversion of glycogen to to glucose, thus raising blood-glucose concentration.


Define the term "β-cell”.

Beta cell - present in the islets of langerhans (endocrine tissue), they produce and secrete insulin, which stimulates the conversion of glucose to glycogen, thus lowering blood-glucose concentration.


Define the term “Islet of Langerhans”.

Specialised cells within the pancreas responsible for producing insulin and glucagon. Endocrine tissue.


Define the term “acinus”.

Exocrine tissue in the pancreas. A small sac-like cavity surrounded by secretary cells. Produces digestive enzymes.


Define the term "tubule/ central duct".

Central duct - exit way for enzymes produced by acini tissue into the small intestine (duodenum).


Define the term “pancreatic duct”.

Same as central duct - a tube leading from the pancreas to the duodenum.


Define the term “insulin”.

A globular protein hormone involved in the regulation of blood-glucose concentration (responsible for the conversion of glucose to glycogen).


Define the term "glucagon".

A hormone found in the pancreas which promotes the break down of glycogen to glucose.


State which cells monitor blood glucose levels.

Alpha and beta cells.


State which cells monitor blood glucose levels.

Alpha and beta cells.


State the normal blood glucose concentration.

90mg cm-3 of blood.


Define the term “hepatocyte”.

Liver cells, take up 70 - 85% of liver's mass.


Name the two hormones involved in regulating blood glucose concentration.

Insulin, glucagon.