Endocrine System

6 Pages
Unlock Document

McMaster University
Danny M.Pincivero

Chapter 17 – The Functional Organization of the Endocrine System What are the characteristics of the endocrine system? - Glands that secrete chemical messengers (hormones) into circulatory system o Directly changes cell physiology  Hormone characteristics o Produced in small quantities o Secreted into intercellular space o Transported some distance in circulatory system o Acts on target tissues elsewhere in body o Regulate activities of body structures • Ligands: more general term for chemical signals --------------------------------------------------------------------------------------------------- What are the similarities and differences between the nervous and endocrine systems? Similarities Differences 1. Both systems associated w/ the brain 1. Mode of transport - Hypothalamus (regulated functions, - Axon (N.S.) secretes hormones) - Blood (E.S.) - Epithalamus (olfaction, melatonin) 2. Speed of Response 2. May use same chemical messengers - Instant/milliseconds (N.S.) as neurotransmitter and hormone - Delayed/seconds (E.S.) - Epinephrine (sympathetic 3. Duration of response [neurotransmitter], adrenal gland - Millisecond/seconds (N.S.) [hormone] - Minutes/days (E.S.) 3. Two systems are cooperative 4. Amplitude vs. frequency - N.S. secretes neuroendocrine peptides - Frequency-modulated (N.S.) or neurohormones into circulatory - Amplitude-modulated (E.S.) system - Some parts of E.S. innervated directly by N.D. (adrenal gland) What are the general characteristics of hormones? 1. Stability o Half-life  Long half-life > usually lipid soluble  Short half-life > water-soluble hormones, rapid onset and short duration 2. Communication - Interaction with target cell (must have cell recognition – binding sites) 3. Distribution - Dissolve in blood plasma and are transported in unbound or are reversibly bound to plasma proteins (eg. lipid soluble – steroid hormones) - Distribute quickly What are the three patterns of hormone secretion? 1. Chronic Hormone Regulation - Relatively constant - Thyroid hormone 2. Acute Hormone Regulation - Epinephrine in response to stress 3. Episodic (Cyclic) Hormone Regulation - Female reproductive hormones --------------------------------------------------------------------------------------------------- How is hormone secretion regulated? - Negative feedback  3 Methods o The action of a substance other than a hormone on an endocrine gland  Humoral stimuli (blood-borne) – eg. glucose o Neural control of endocrine gland  Adrenal gland (medulla) o Control of secretory activit of one endocrine gland by hormone or by another endocrine gland  Anterior pituitary gland Chapter 18 – Endocrine Glands What role do the pituitary gland and hypothalamus play? - Hypothalamus regulated secretions of anterior pituitary  Posterior Pituitary o Neurohypophysis  Produces 2 major hormones o Extension of hypothalamus  Anterior Pituitary o Adenohypophysis  Produces 9 major hormones --------------------------------------------------------------------------------------------------- How is ADH secretion regulated?  Osmoreceptors o Sensors in hypothalamus o Sensitive to intercellular osmolality (concentration of solutes)  Baroreceptors o Atria, carotid artery, aortic arch o Sensitive to blood pressure - Negative feedback – restoration of blood (plasma)  in blood osmolatilty,  in blood pressure posterior  Hypothalamic neuron  Hypothalamohypophysial tract  Posterior pituitary   ADH secretion  Kidney   urine volume  urine osmolatility  blood osmolatility  blood volume and blood pressure How is oxytocin secretion regulated?  Osmoreceptors - Sensors in hypothalamus  Baroreceptors - Atria, carotid artery, aortic arch o Stimuli
More Less

Related notes for KINESIOL 1YY3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.