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Biology 2 > 4. Hormonal Communication > Flashcards

4. Hormonal Communication Flashcards

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1
Q

What are sensory receptors?

A

Specialised cells that can detect changes in our surroundings.

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2
Q

What are hormones?

A

Substances that stimulate target cells via the blood.
They are released directly into the blood plasma from endocrine glands.
Each hormone has specific target cells on which it acts.

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3
Q

What are the two types of hormone?

A

Protein/ Peptide hormones and Steroid hormones

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4
Q

What are protein/ peptide hormones?

A

They are non-soluble in the phospholipid membrane and do not enter the cell.
They bind to the cell surface membrane and release a second messenger inside the cell.

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5
Q

What are steroid hormones?

A

They can pass through the membrane and enter the cell.

This is because they contain steroid in their structure which helps them pass through the phospholipid bilayer.

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6
Q

What are Endocrine glands?

A

Release hormones directly into the blood.

They do not contain ducts.

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7
Q

What are Exocrine glands?

A

Contain ducts that carry products straight to target cells in the epithelial layers of internal or external body surfaces.
Exocrine glands do not produce hormones.

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8
Q

What are adrenal glands?

A

Endocrine glands found on the interior of the kidneys.

Each gland is divided into the outer adrenal cortex and the inner adrenal medulla.

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9
Q

What is the the structure and function of the adrenal cortex?

A

Zona Glomerulosa,
Outer layer- secretes mineralocorticoids.
Zona Fasciculat,
Middle layer- secretes glucocorticoids.
Zona Reticularis,
Inner layer- secretes precursor molecules.

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10
Q

What is the structure and function of the adrenal medulla?

A

Found at the centre of the adrenal gland.

Secretes adrenaline and noradrenaline.

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11
Q

What is the function of adrenaline?

A

It prepares the body for fight or flight.

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12
Q

How does adrenaline act on the cell?

A
  1. Binding of adrenaline (first messenger) alters the shape of the receptor.
  2. This causes the G protein to split and combine with the inactive enzyme adenyl cyclase.
  3. Adenyl cyclase converts ATP to cyclic AMP (second messenger).
  4. cAMP can act directly on another protein e.g. ion channels or may initiate a cascade of enzyme-controlled reactions.
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13
Q

What does adrenaline trigger?

A

Relaxing smooth muscles in the bronchioles, Increasing stroke volume of the heart, Dilating the pupils, Stimulating conversion of glycogen to glucose.

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14
Q

What is the function of the pancreas?

A

Has both an endocrine and exocrine function
Exocrine function- releases digestive enzyme-containing pancreatic juices from the acinus into the small intestine.
Endocrine function- Islets of Langerhans contain alpha and beta cells.
Alpha cells- secrete glucagon
Beta cells- secrete insulin.

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15
Q

What enzymes does the fluid excreted from the pancreas contain?

A

Amylase- Catalysis hydrolysis of amylose to maltose.
Lipase-Catalysis hydrolysis of lipids to fatty acids and glycerol.
Trypsinogen- Catalyses hydrolysis of proteins to polypeptides.

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16
Q

What is the function of Insulin?

A

It reduces blood glucose concentration.

If blood glucose levels are too high, then insulin is release from the beta cells.

17
Q

What cells detect when blood glucose levels are too high or too low?

A

High blood glucose is detected by the beta cells in the islets of Langerhans.

18
Q

How do beta cells secrete insulin?

A

If blood glucose levels become too high, glucose moves into the cell.
Glucose is metabolised into ATP which closes potassium channels.
The accumulation of potassium alters the potential difference and opens calcium channels.
Calcium ions cause vesicles of insulin to fuse with the cell wall and release insulin.

19
Q

How does insulin stimulate the cell?

A

It binds to specific membrane-bound receptors and activates the enzyme tyrosine kinase inside the cell.
Tyrosine kinase causes the phosphorylation of inactive enzymes in the cell.
This activates vesicles containing transporter proteins to bind to the membrane, allowing extra glucose to enter the cell.

20
Q

What effect does insulin have on the cell?

A

More transport of Glucose into the cell.
Glycogenesis- Glucose is converted to glycogen for storage
More glucose is used in respiration

21
Q

How does the body respond to low blood glucose levels?

A

Alpha cells secrete glucagon into the blood.
Glucagon binds to specific receptors and stimulates a G protein inside the cell.
This activates adenyl cyclase inside the cell.
Adenyl cyclase converts ATP to cAMP, which activates a series of enzyme-controlled reactions in the cell.

22
Q

What is done to increase blood glucose levels?

A

Glycogenolysis- Enzyme phosphorylase A is activated and converts glycogen to glucose.
Gluconeogenesis- Amino acids and fats are converted into additional glucose.

23
Q

What are the two types of diabetes?

A

Type 1- Insulin-dependent diabetes

Type 2- Insulin-independent diabetes

24
Q

Who usually gets type 1 diabetes?

A

Usually occurs in younger people.

25
Q

Who usually gets type 2 diabetes?

A

Old people, obese people.

26
Q

What are the causes of Type 1 diabetes?

A

Can be born with it or be a result of an autoimmune response where the immune system destroys beta cells.
Excess glucose is not removed quickly, leaving a prolonged period of high concentration.
When blood glucose falls, there is no store of glycogen to release glucose, so blood glucose levels fall too low.

27
Q

What are the causes of Type 2 diabetes?

A

The person can produce insulin, but not enough.

Responsiveness to insulin declines as the receptors on the liver and muscle cells become less responsive.

28
Q

What factors result in Type 2 diabetes?

A

Obesity, Lack of exercise, High sugar diet, Being Asian or Afro-Caribbean origin, Family history

29
Q

What are the treatments for Type 1 diabetes?

A

Insulin injections, Insulin pump therapy, Islet cell transplantation, A complete pancreas transplant

30
Q

What are insulin injections?

A

The correct dose of insulin is administered to keep glucose concentration stable.

31
Q

What is Insulin pump therapy?

A

Constantly pumping insulin into the bloodstream at a controlled rate.

32
Q

What is Islet cell transplantation?

A

Healthy beta cells from the pancreas from a donor are implanted into the pancreas.

33
Q

What are the treatments for type 2 diabetes?

A

Changes in lifestyle, (weight loss, exercise)
Monitor diet (sugar and carbohydrate intake)
Medication- reduces the amount of glucose the liver releases or boosts the amount of insulin secreted from the pancreas.

Biology 2 (12 decks)

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