HB TOPIC 1 NERVOUS/ENDOCRINE

1. What is the ROLE of the endocrine system

• Influences the activity of cells by the release of hormones to maintain homeostasis

1. What are the 2 types of gland?

   • List them

   • Explain each

   • Examples

1. Exocrine glands- secretes hormones through ducts to body durface or cavities- eg. Sweat glands, salivary glands, mucous glands

2. Endocrine glands- secretes hormones into extracellular fluid that sirrounds the cellls that make up the gland. Eg. Pancreas, testes, pineal gland.

1. Define Hormones

   • how are they transported

Chemicals secreted by specialized cells, which contain proteins, amines, or steroids- TRANSPORTED BY BLOOD.

1. Steps of STEROID hormones

1. Enter target cell

2. Combine with receptor protein in cell

3. Hormone receptor complex (HRC) enters nucleus

4. HRC activates genes that control protein synthesis

5. Transcription

6. Translation and protein produced

1. How do steroid hormones change function of cell?

1. Type of protein by activating genes to prod enzymes/proteins

2. Role of proteins by changing structure

3. Change rate of enzyme/protein prod.

1. Steps of Protein and amine hormones

1. Attach to protein receptor on cell membrane of target cell

2. Secondary messenger diffuse through cell

3. Specific enzymes activated

4. Cellular function is affected

1. How do protein receptors prevent continual increase in cell activity?

• Specific lock and key

• Cells have different numbers and types of protein receptors varying response to different hormones

• Limited number of PR in each membrane

1. Define ezyme amplification

• one hormone can activate billions of enzymes which can trigger more and more

1. Define hormone clearence and where it occurs

• Break down of hormones after they have indicated a response

• Most broken down via liver and kidney or target cell and excreted in bile or urine.

2. Pituitary gland- where is it located and how is connected?

• below hypothalamus and connected via a thin stalk called Infundibulum

Label the parts

1. Hypothalamus

2. Pituitary

3. Pineal

4. Thyroid and parathyroid

5. thymus

6. Pancreas

7. Adrenal cortex and medulla

8. ovary

9. placenta

10. testicles

2. Structure of Pituitary gland and how is connected to hypothalamus

2 lobes

1. Anterior Lobe- connected via blood vessels

2. Posterior Lobe- connected via nerve fibres

2. Anterior Lobe

   • how is it controlled and examples of hormones released

1. Controlled by releasing and inhibiting factors from hypothalamus into blood into anterior

2. TPFLAG

2. TSH

   • target organ

   • role

• thyroid and parathyroid

• stimulates release of hormones

2. FSH

   • target organ

   • role

• ovaries and testes

• stimulates growth and maturation of follicles/sperm and release of hormones

2. Luteinising hormone

   • target organ

   • role

• ovary

• stim of ripe follicle and prod of corpus leuterm

• stim prod of eostrogen and progesterone

2. Growth hormone

   • target organ

   • role

• most tissues

• growth in size and mass

• increases fat utilization and decreases glucose utalization

2. Prolactin

   • target organ

   • role

• mammary glands

• promotes growth of mammary and milk secretion

2. Adrenocorticotropic hormone

   • target organ

   • role

• adrenal cortex

• stim prod and secretion of corticosteroids

2. Posterior Lobe

   • how is it controlled

   • examples of hormones released

• hormones produced in hypothalamus and stored in posterior lobe

• oxytocin, ADH

2. Thyroid Gland

   • what does it secrete and how is it stimulated

• Thyroxine (T4), T3 and Calcitonin

• Stimulated by TSH

2. Thyroxine and T3 HORMONE

   • target organ

   • effect

• Small intestine

• Controls metabolism and synthesis, increased absorption of of glucose

2. Calcitonin

   • target organ

   • function

• bones, intestine

• decrease blood calcium levels by excretion in urine and decreases calcium absorb in intestines

2. Parathyroid gland

   • secretes what hormone

   • effect

     • stimulated by…

• secretes parathyroid hormone

• controls blood calcium and phosphate levels

• TSH

2. Pancreas

   • 2 types

   • secretes what hormones?

Exocrine- digestive enzymes into small intestine

Endocrine- Islet of Langerhans secrete insulin and glucagon

2. Difference between insulin and glucagon in terms of

   • produced by…

   • role

   • impact on blood sugar levels

1. Insulin produced by beta cells- converts glucose into glycogen and fat= DECREASE BSL

1. Glucagon produced by alpha cells- glycogen and fat into glucose= INCREASE BSL

2. Testes

   • hormone secreted

   • role of hormone

• secrete testosterone

• develop and maintain features

2. Ovaries

   • hormone secreted

   • effect of hormones

• oestrogen and progesterone

• develop and maintain female features, regulate menstrual cycle and changes during pregnancy

2. Pineal Gland

• secretes what hormone

• role of hormone

• how is it stimulated

• melatonin

• regulated sleep patterns

• stim by darkness

2. Adrenal Medulla

   • secretes what hormones

   • effect of hormone

• adrenaline and noradrenaline

• stimulates fight or flight response and responses (HR)

2. Adrenal Cortex

   • secretes what hormones

   • role of each

• cortico steroids of

• 1. Cortisol- promotes metabolism, stress and repair damaged tissue inbody cells

• 2. Aldosterone- kidneys to increase pottasium and decrease sodium in urine

Thymus

• secretes what hormone

• role of hormone

• what happens after purbety

• thymosins

• maturation of T lymphocytes

• shrinks after puberty