Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Chapter 23  Adrenal glands  Thyroid hormones  Growth hormone  Tissue and bone growth  Calcium balance

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Review of Endocrine Principles  Hypothalamic-pituitary control system  Several hormones controlled by hypothalamic and anterior pituitary trophic hormones  Feedback patterns  Negative feedback:  Simple Pathway-Blood glucose level decreasing shuts off insulin secretion  Complex Pathway-use the hypothalamic-pituitary control system, where the feedback signal may be the hormone itself  Hormone receptors  May be on surface or inside the cell  Cellular responses  Target cells respond by altering existing proteins or making new proteins  Magnitude of target cell response  Depends on number of receptors and amount of active hormone  Endocrine pathologies  Excess hormone secretion  Inadequate hormone secretion  Abnormal target cell response to the hormone

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Adrenal Glands Structure and function of the adrenal gland Figure 23-1a

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-1b Adrenal Glucocorticoids

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-1c Adrenal Glands

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Adrenal Cortex Secretes Steroid Hormones 1.Aldosterone (Mineralcorticoid) 2.Glucocorticoids  Cortisol 3.Sex Hormones

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-2 Adrenal Glucocorticoids Synthesis pathways for steroid hormones

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-3 Cortisol The HPA pathway for the control of cortisol secretion Corticotropin Releasing Hormone Adrenocorticotropic Hormone

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-4 Circadian Rhythm of Cortisol Secretion

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Cortisol

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Cortisol  Promotes gluconeogenesis  Causes breakdown of skeletal muscle proteins  Enhances lipolysis  Suppresses the immune system  Causes negative calcium balance  Influences brain function

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Cortisol: Therapeutic Drug  Suppresses the immune system  Inhibits the inflammatory response  Used to treat  Bee stings, poison ivy, and pollen allergies  Prevents rejection of transplanted organs

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Hypercortisolism Hypercortisolism: Excess cortisol in the body Cushings Syndrome: Hormonal disorder caused by prolonged exposure to excess cortisol (including iatrogenic).  Signs and Symptoms  Hyperglycemia  Muscle protein breakdown  Excess deposits of extra fat in trunk and face  Thin arms and legs  Thin skin and bruising Three causes of hypercortisolism:  Adrenal tumor that autonomously secretes cortisol (Primary Hypercortisolism)  Pituitary tumor that autonomously secretes ACTH (Secondary Hypercortisolism or Cushing’s Disease)  Iatrogenic hypercortisolism

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-5 Hypercortisolism

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Hypocortisolism  Less common than Cushing’s syndrome  Addison’s disease  Hyposecretion of all adrenal steroid hormones  Autoimmune destruction of adrenal cortex

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid: Structure Figure 23-7a

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid: Structure Figure 23-7b

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-8 Thyroid Thyroid hormones are made from iodine and tyrosine

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Thyroid

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Hyperthyroidism  Increases oxygen consumption and metabolic heat production  Increase protein catabolism and may cause muscle weakness  Hyperexcitable reflexes and psychological disturbances  Influence  -adrenergic receptors in the heart

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Hypothyroidism  Slow metabolic rate and oxygen consumption  Decreases protein synthesis  Slowed reflexes, slow speech and thought processes, and feelings of fatigue  Cretinism in infants  Bradycardia

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Pathway of Thyroid Hormone Control

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Thyroid A man with goiter due to excessive TSH stimulation

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-14a Thyroid Goiter can occur in both hyperthyroidism and hypothyroidism

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23-14b Thyroid

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Normal Growth  Growth hormone and other hormones  An adequate diet  Absence of stress  Genetics

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Pathway of Growth Hormone Control

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Growth Hormone

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Growth Hormone  Severe GH deficiency leads to dwarfism  Oversecretion of GH in children leads to giantism  Oversecretion of GH in adults leads to acromegaly

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Three Individuals with Acromegaly

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Bone growth Linear growth of long bones takes place at the epiphyseal plates Epiphysis is the end of a long bone. Diaphysis is the shaft of a long bone. Epiphyseal plate is the site of bone growth. Diaphysis Compact bone Osteoblast Direction of growth Chondrocyte Cartilage owth Newly calcified bone Bonegr Dividing chondrocytes add length to bone. Chondrocytes produce cartilage. Old chondrocytes disintegrate. Osteoblasts lay down bone on top of cartilage.

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (1 of 5) Bone growth Epiphysis is the end of a long bone. Diaphysis is the shaft of a long bone. Epiphyseal plate is the site of bone growth. Diaphysis

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (2 of 5) Bone growth Epiphysis is the end of a long bone. Diaphysis is the shaft of a long bone. Epiphyseal plate is the site of bone growth. Diaphysis Compact bone Chondrocyte Dividing chondrocytes add length to bone.

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (3 of 5) Bone growth Epiphysis is the end of a long bone. Diaphysis is the shaft of a long bone. Epiphyseal plate is the site of bone growth. Diaphysis Compact bone Chondrocyte Cartilage Dividing chondrocytes add length to bone. Chondrocytes produce cartilage.

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (4 of 5) Bone growth Epiphysis is the end of a long bone. Diaphysis is the shaft of a long bone. Epiphyseal plate is the site of bone growth. Diaphysis Compact bone Chondrocyte Cartilage Dividing chondrocytes add length to bone. Chondrocytes produce cartilage. Old chondrocytes disintegrate.

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (5 of 5) Bone growth Epiphysis is the end of a long bone. Diaphysis is the shaft of a long bone. Epiphyseal plate is the site of bone growth. Diaphysis Compact bone Osteoblast Direction of growth Chondrocyte Cartilage owth Newly calcified bone Bonegr Dividing chondrocytes add length to bone. Chondrocytes produce cartilage. Old chondrocytes disintegrate. Osteoblasts lay down bone on top of cartilage.

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Calcium Balance

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Calcium  Important signal molecule  Part of intercellular cement that holds cells together at tight junction  Cofactor in the coagulation cascade  Affects the excitability of neurons

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Calcium Balance in the Body Ca 2+ Small intestine Dietary calcium Calcium in feces [free Ca 2+ ] mM Kidney Ca 2+ in urine Ca 2+ in kidney tubules Calcitrol (PTH, prolactin) Active transport Some calcium is secreted into the small intestine. Cells [Ca 2+ ] 2.5 mM Passive filtration Calcitonin Ca 2+ PTH Calcitonin PTH Calcitriol Cortisol Bone ECF Electrochemical gradient PTH = parathyroid hormone KEY

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (1 of 5) Calcium Balance in the Body [Ca 2+ ] 2.5 mM ECF PTH = parathyroid hormone KEY

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (2 of 5) Calcium Balance in the Body [free Ca 2+ ] mM Active transport Cells [Ca 2+ ] 2.5 mM ECF Electrochemical gradient PTH = parathyroid hormone KEY

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (3 of 5) Calcium Balance in the Body [free Ca 2+ ] mM Active transport Cells [Ca 2+ ] 2.5 mM Calcitonin Ca 2+ PTH Calcitriol Cortisol Bone ECF Electrochemical gradient PTH = parathyroid hormone KEY

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (4 of 5) Calcium Balance in the Body Ca 2+ Small intestine Dietary calcium [free Ca 2+ ] mM Calcitrol (PTH, prolactin) Active transport Cells [Ca 2+ ] 2.5 mM Calcitonin Ca 2+ PTH Calcitriol Cortisol Bone ECF Electrochemical gradient PTH = parathyroid hormone KEY

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure (5 of 5) Calcium Balance in the Body Total body calcium = intake  output Ca 2+ Small intestine Dietary calcium Calcium in feces [free Ca 2+ ] mM Kidney Ca 2+ in urine Ca 2+ in kidney tubules Calcitrol (PTH, prolactin) Active transport Some calcium is secreted into the small intestine. Cells [Ca 2+ ] 2.5 mM Passive filtration Calcitonin Ca 2+ PTH Calcitonin PTH Vitamin D Cortisol Bone ECF Electrochemical gradient PTH = parathyroid hormone KEY

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Calcium Balance Osteoclasts are responsible for bone resorption

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Calcium Balance  Parathyroid hormone  Mobilizes calcium from bone  Enhances renal reabsorption  Indirectly increases intestinal absorption  Vitamin D (Calcitriol)  Calcitonin (from Thyroid)

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Calcium Balance: Parathyroid Glands

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Calcium Balance

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Endocrine Control of Calcium Balance

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Calcitonin

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure Osteoporosis Normal bone (left) and bone loss in osteoporosis (right)