Homeostasis is dependent on and nervous control

© 2016 Pearson Education, Inc. (b) Signaling by neurons STIMULUS Cell body of neuron Nerve impulse Axon Signal travels to a specific location. Nerve impulse Figure 32.4b Signaling in the endocrine and nervous systems Axons Response © 2016 Pearson Education, Inc.

© 2016 Pearson Education, Inc. (a) Signaling by hormones STIMULUS Endocrine cell Hormones -molecules produced by endocrine glands, enter blood and have effect on target cells Hormone Signal travels everywhere. Blood vessel Figure 32.4a Signaling in the endocrine and nervous systems Response © 2016 Pearson Education, Inc.

Peptide based hormones Use signal transduction pathways Utilize second messengers

Steroid hormones

© 2016 Pearson Education, Inc. Thyroid gland Pineal gland Hypothalamus Thyroid hormone (T3 and T4 ) Melatonin Calcitonin Pituitary gland Parathyroid glands Posterior pituitary Parathyroid hormone (PTH) Oxytocin Vasopressin, also called antidiuretic hormone (ADH ) Adrenal glands (atop kidneys) Adrenal medulla Epinephrine and norepinephrine Anterior pituitary Adrenal cortex Follicle-stimulating hormone (FSH) Glucocorticoids Mineralocorticoids Luteinizing hormone (LH) Thyroid-stimulating hormone (TSH) Ovaries (in females) Estrogens Adrenocorticotropic hormone (ACTH) Figure 32.5 The human endocrine system Progesterone Prolactin Growth hormone (GH) Testes (in males) Melanocyte-stimulating hormone (MSH) Androgens Pancreas Insulin Glucagon © 2016 Pearson Education, Inc.

© 2016 Pearson Education, Inc. Simple endocrine pathway Example: secretin signaling STIMULUS Low pH in duodenum Endocrine cell S cells of duodenum Negative feedback Hormone Secretin ( ) Circulation via blood Figure 32.6 A simple endocrine pathway Target cells Pancreatic cells RESPONSE Bicarbonate release © 2016 Pearson Education, Inc.

Some hormones work in antagonistic pairs ex: insulin / glucagon calcitonin / PTH

Neuroendocrine signaling involves the hypothalamus and the pituitary gland

© 2016 Pearson Education, Inc. Simple neuroendocrine pathway Example: oxytocin signaling STIMULUS Suckling Neurosecretory cell Hypothalamus Posterior pituitary Hormone Positive feedback Blood vessel Oxytocin ( ) Circulation throughout body via blood Figure 32.7 A simple neuroendocrine pathway Target cells Smooth muscle in mammary glands RESPONSE Milk release © 2016 Pearson Education, Inc.