Define Exocrine glands
Glands with ducts
-sweat,mammary, salivary glands
Define Endocrine glands
Ductless glands
-secrete hormones directly into the blood
How many major endocrine glands are there
9
5 things hormones regulate
- Reproduction
- Growth and Development
- Maintaining homeostasis
- Regulation of energy availability
- Aid in the survival of stress
5 Potential hormone actions
- Cause a change in membrane permeability by opening or closing ion channels
- Protein synthesis
- Activate/deactivate enzymes
- Induce secretory activity of glands
- stimulate mitosis
3 Basic stimuli for release
- Humoral stimuli- levels in blood
- Hormonal stimuli- hormone levels in blood
- Neural stimuli
Monoamine hormones
- Amino acid baked
- water soluble
- second messenger system (except T3 &4)
Steroid hormones
- made from cholesterol
- lipid soluble
- direct gene activation
Describe the second messenger system
Water soluble hormone binds to receptors on the outside of the cell–> G protein is activated –> G protein then activates adenylate cyclase, which produces cAMP –> cAMP activates ezymes called protein kinases which will then phosphorylate other enzymes–> cAMP is then quickly broken down by phosphodiesterase
Describe direct gene activation
The receptor binds the hormone in the nucleus –> leads to protein synthesis:
DNA–> mRNA–> Protein –> Action
What are the two master glands?
Pituitary and Hypothalamus (connected by the infiundibulum)
What are the two lobes of the pituitary gland
- Posterior (Neurohypophysis)
2. Anterior (Adenohypophysis)
What are the two nuclei within the hypothalamus
- Supraoptic nuclei (makes ADH)
2. Paraventricular nuclei (makes OT)
Posterior lobe of the pituitary gland (Neurohypophysis)
- Made of neural tissue (can’t make own hormones)
- Maintains a neural connection with the hypothalamus- it has axons coming from the hypothalamic unclei that deliver hormones for storage and release
- formed by down-growth off the hypothalamus
- Hormones travel through hypothalamic-hypophyseal tract
Oxytocin (OT)
-RELEASED by post pit.
-MADE by hypothalamus
Functions:
- uterine contractions during labor and sex
-stimulates let down reflex for milk
-Positive feedback loop during labor
(Pitocin OT in drug form )
Antidiuretic hormone (ADH)
-RELEASED by post pit.
-MADE by hypothalamus
Functions:
- decreases urine output
(lack of ADH causes diabetes insipidus)
Anterior Pituitary (Adenohypophysis)
- made of glandular tissue (makes own horm. but release is controlled by hypothalamus)
- Connected to hypo by vascular connection called the hypophyseal portal system
- develops as an offshoot of the oral mucosa
Define the portal system
Capilaries–>Veins–> Capillaries
6 releasing & inhibiting hypothalamic hormones
- Thyrotopin-releaseing hormone TRH
- Corticotropin-releaseing hormone CRH
- Gonadontropin-releaseing hormone GnRH
- Growth-hormone relaseing hormone GHRH
- Growth hormone inhibiting hormone GHIH
- Prolactin-inhibiting hormone PIH (dopamine
4 Tropic hormones of the anterior pituitary
- Thyroid-stimulating hormone TSH
- Andrenocorticotropic hormone ACTH
- Follicle-stiumlating hormone FSH
- Luteinizing hormone LH
2 non tropic hormones of the anterior pituitary
- Prolactin PRL
2. Growth hormone GH
Growth Hormone (GH)
Created and released by anterior pit.
-Diurnal cycle, exercise increases release
Actions:
1.Stimulates AA uptake and stimulates protein synthesis
2. Stimulates fat breakdown for energy
3. inhibits glucose uptake by cells
4. Stimulates bone & cartilage growth
Thyroid Gland produces which 3 hormones
- Thyroxine T4–Follicles
- Triiodothyronine T3–Follicles
- Calcitonin CT–Parafollucular
T3&T4
- increase BMR
- prevents cretinism
- needed for GH to promote normal muscle and bone devl.
- promotes gut mobility
- Work by direct gene activation
- Negative feedback loop*
