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Endocrine System Chp 13.

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Presentation on theme: "Endocrine System Chp 13."— Presentation transcript:

1 Endocrine System Chp 13

2 Endocrine System: Regulates body functions with Hormones
Produced by endocrine glands [e.g. pituitary] Circulate in the blood stream Steroids - lipid soluble Nonsteroids - not lipid soluble Often interact with nervous system Act on specific cells [target cells] in the body

3 Endocrine System Characteristics
Access to every cell Each hormone acts only on specific target cells Target cells have receptors for specific hormones Endocrine control slower than nervous system Endocrine & nervous systems interact

4 Steroid Hormone Action on a Target Cell
Figure 13.2

5 Classification of Hormones: Steroid
Steroid Hormones: Lipid soluble, chemically derived from cholesterol Enter target cells Activate specific genes to produce specific proteins Slower acting than nonsteroid hormones, minutes to hours

6 Nonsteroid Hormone Action on a Target Cell
Figure 13.3

7 Classification of Hormones: Nonsteroid
Nonsteroid hormones: Water soluble Bind to receptors on target cell membranes Work through intermediate mechanisms to activate existing enzymes Faster action than steroid hormones, seconds to minutes

8 Role of Negative Feedback Loops
Figure 13.4

9 Hypothalamus and the Posterior Pituitary Gland
Connection to hypothalamus: hormones made in hypothalamus, stored in posterior pituitary Hormones: nonsteroidal operate here Antidiuretic hormone (ADH): conserves water in kidneys, regulates water balance in body Oxytocin: causes uterine contractions during labor & milk ejection through neuroendocrine reflex

10 Hypothalamus & the Anterior Pituitary Gland
Connection to hypothalamus: releasing and inhibiting hormones from hypothalamus travel to pituitary through pituitary portal system Hormones: nonsteroidal operate here ACTH- stimulates adrenal cortex TSH- acts on thyroid gland FSH, LH, Prolactin- related to control of reproductive cycles and lactation Growth Hormone- widespread effects on body

11 Pituitary Disorders Hypersecretion of ADH - excessive water retention
Diabetes Insipidus - hyposecretion of ADH, inability to conserve water appropriately Gigantism- hypersecretion of growth hormone Pituitary Dwarfism- hyposecretion of growth hormone

12 Pancreas: Endocrine Functions include
Hormones secreted by islets of Langerhans are Nonsteroidal: Glucagon - raises blood sugar Insulin- lowers blood sugar

13 Roles of Insulin and Glucagon in Regulating Blood Glucose
Figure 13.9

14 Adrenal Glands: 2 small endocrine glands located just above kidneys
Adrenal cortex - secretes steroid hormones Produces small amounts of estrogen & testosterone Produces: Cortisol [regulates blood glucose] Aldosterone [regulates sodium & potassium]

15 Adrenal Glands: Medulla
Adrenal medulla- secretes nonsteroid hormones Secretion: stimulated by sympathetic nervous system Nonsteroidal hormones that control metabolism, blood pressure & heart rate Epinephrine [adrenaline] Norepinephrine They both enhance function of sympathetic nervous system (Fight or Flight Response)

16 Thyroid Gland Secretion: mediated through hypothalamus-pituitary secretions Secretes Steroidal hormones: Thyroxine (T4) and Triiodothyronine (T3) - both regulate production of ATP from glucose, affects metabolic rate Calcitonin: lowers blood calcium levels

17 Parathyroid Glands Secretion: response to lowered blood calcium levels
Hormone: Parathyroid hormone (PTH), nonsteroidal Removes calcium and phosphate from bone Increases absorption of calcium by the digestive tract Increases renal retention of calcium and excretion of phosphate

18 Testes Hormone secreted = Testosterone (steroidal) Functions:
Regulates development and normal functioning of sperm, male reproductive organs, male sex drive Development of male secondary sex characteristics

19 Ovaries Hormones (steroidal) & functions:
Estrogen- initiates development of secondary sex characteristics, regulates menstrual cycle Progesterone - regulates menstrual cycle

20 Other Chemical Messengers
Histamine - inflammation Prostaglandins - local control of blood flow Growth factors - local acting/ mitotic activity

21 Disorders of the Endocrine System
Thyroid Disorders: Hypothyroidism - underactivity of thyroid Children: slows body growth, brain development & delays puberty Adults: causes edema, weight gain, lethargy, low body temp. Hyperthyroidism: [Graves Disease] Overactive thyroid Causes- Increased BMR, hyperactivity, nervousness, weight loss

22 Adrenal Gland Disorders:
Addison’s Disease: failure of adrenal cortex to secrete sufficient cortisol & aldosterone Lowers blood glucose & sodium Symptoms: Chronic fatigue, weakness, weight loss & abdominal pain Cushing’s Syndrome: excessive cortisol produced High blood glucose & reduced muscle mass Retension of too much salt & water Symptoms: weakness & fatigue, edema, high blood pressure

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