Final exam study guide (old mat) Flashcards
What is the endocrine system?
o The endocrine system are glands, tissues, and cells that secrete hormones. Hormones are chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ, often a considerable distance away. The endocrine system reacts slowly (seconds or days), effects may continue for days or longer. Endocrine system has a general, widespread effects (many organs). Hormones are chemical messengers that are transported by the bloodstream and stimulate physiological responses in cells of another tissue or organ.
- How are exocrine and endocrine glands formed? How do the cells of these glands secrete products differently?
o Glands arise from the formation of pocketlike invaginations of surface epithelial cells. If the connecting cellls remain and the gland releases the product through the connecting duct to the surface, an exocrine gland is formed. If the connecting cells are lost and the gland releases the product into the blood, an endocrine gland is formed.
How do hormones get into the blood plasma?
o Secretions of endocrine cells move directly into the ISF which is directly outside most cells. From the ISF, hormones move into the blood plasma within capillaries.
- What cells can hormones interact with (what are they called)? Do they have only one effect on any given cell?
o Hormones can only interact with Target Cells that express specific receptor proteins specifically bind that hormone. Only cells having appropriate receptor proteins will be able to respond to a given hormone.
- There are different classes of hormones, you do not need to memorize the names of the different classes.
o Peptide hormones- insulin, glucagon.
o Catecholamines- epinephrine, norepinephrine, dopamine
o Indoleamines- melatonin
o Steroids- estrogen, testosterone, aldosterone
o Eicosanoids- prostaglandins
- What concentration of hormones are necessary for them to do their job? How is it so different from neurotransmitter concentration?
o Most hormones are effective at extremely low concentrations (10^-8 to 10^-12 molar within the ISF is effective.) In comparison, most NTs are present w/in the synaptic cleft at concentrations of approximately 10^-4 molar
- What are pharmacological concentrations? What are some unintended effects of taking exogenous hormones like anabolic steroids?
o Pharmacological concentrations are hormone concentrations that can only be achieved by taking exogenous hormones.
o Taking anabolic steroids- exogenous testosterone used by body builders, Aromatase enzyme converts testosterone into estrogen, resulting estrogen causes Gynecomastia.
- Why is the pituitary gland called the “master gland” of the body?
o Because it controls many other endocrine organs
Infundibulum
the pituitary gland is suspended from the hypothalamus by a stalk
Sella turcica
Where the pituitary gland hangs out
Hypophysis
the pituitary
adenohypophysis
anterior pit
Neurohypophysis
post pit
The anterior and posterior pituitary gland have different names and look different. This is due to how they are created during early development. How does each part form?
o The post. Pituitary is an extention of neural tissue from the hypothalamus. The ant. Pituitary is a true endocrine gland of epithelial origin- formed from the roof of the embryonic mouth
- What is a neurohemal organ? Are they important?
o How a neurohormone (a hormone secreted by a neuron cell) gets into the blood stream. Goes through a fenestrated capillary at a neurohemal organ. And they are important.
nah id go through fenestrated capillaries
- There are two areas of the hypothalamus that house the cell bodies of neurosecretory neurons whose axons terminals form the posterior pituitary gland. Do you remember the names of these two nuclei?
o Supraoptic and paraventricular
- What is a pituicyte?
o Glial cells that (along with the axon terminals of neuroendocrine cells) form the post. Pituitary
- What are the two different hormones produced by the neurons in the posterior pituitary?
o Oxytocin and Antidiuretic Hormone (ADH) aka arginine vasopressin (AVP)
What does oxytocin do?
triggers maternal uterine contractions during childbirth
Triggers milk ejection from breast during suckling
May affect some male paternal behaviors
Secretion of oxytocin is stimulated by dilation of cervix, stimulation of nipples, or the sound of a hungry baby crying.
Antidiuretic hormone (ADH)
Increases water reabsorption by the kidneys
Causes vasoconstriction of arterioles
- Tropic vs non-tropic hormones
o Tropic- other endocrine glands as the target
o Non-tropic- hormones directly stimulate target cells
- The anterior pituitary has endocrine cells that secrete a number of different hormones. Do you remember what they are? (there is a mnemonic device)
o FLAT PiG ME
Follicle-stiumlating hormone (FSH)
* Testes/ovaries
Lutenizing Hormone (LH)
* testes/ovaries
Adrenocorticotropic hormone (ACTH)
* Adrenal cortex
Thyroid-stimulating hormone (TSH)
* thyroid
Prolactin
* Mammary glands
Ignore I
Growth hormone (GH)
* Liver, bones, other tissues
Melanocyte-stimulating hormone (MSH) (from pro-opiomelanocortin)
* melanocytes
Endorphin (from pro-opiomelanocortin)
- Typically, each endocrine cell in the anterior pituitary secretes a different hormone. There are some that secrete more than one. Do you remember what gonadotrophs and corticotrophs secrete?
o Gonadotrophs secrete FSH and LH (follicle-stimulating and luteinizing)
o Corticotrophs secrete ACTH, MSH, and Endorphins (adrenocorticotropic, melanocyte-stimulating)
- What is a Pro-opiomelanocortin?
o Its a pro-peptide that has been chopped off a pre-pro-protein
- What does the term hypophysiotropic mean? These are hormones secreted by neurosecretory neurons in the hypothalamus. What do they do?
o Hypophysiotropic- hormones that are secreted by neurosecretory neurons w/in the hypothalamus (pituitary regulating). Either stimulate (releasing hormones) or inhibit (inhibiting hormones) the secretion of hormones from the ant. Pituitary endocrine cells.
- What is the portal vessel system and what is the advantage of it? (We discussed two things).
o Hypothalamic-Hypophyseal Portal Vessel System- vascular link between hypothalamus and ant. Pituitary gland.
Neurohemal organ w/in the median eminence picks up tropic hormones secreted by hypothalamic neurons
A Portal System carries these hypophysiotropic hormones to the Ant. Pituitary
A capillary bed w/in the Ant. Pituitary allows its secreted hormones to enter the systemic circulation
o Important functional advantages of a portal system: NO dilution of hormone, NO enzymatic destruction of hormone by the liver or lungs.
- Negative feedback loops play an important role in regulating the secretion of hormones. Do you understand the negative feedback loop with the thyroid?
o The hypothalamus secretes TRH (thyrotropic-releasing hormone)
o TRH triggers section of TSH (thyroid stimulating hormone) from the ant. Pituitary
o TSH triggers secretion of Thyroxin from the thyroid gland
o Thyroxin inhibits the responsiveness of the ant. Pituitary to TRH, and inhibits secretion of TRH by the hypothalamus.
- The pericardium encloses the heart and has different layers. Do you know what they are and what they do? Where would you find fluid?
o Fibrous pericardium
o Serous pericardium
Parietal layer- lines fibrous pericardium
Fluid in between these two guys
Visceral layer (epicardium)- covers heart surface
- Be sure that you understand the general anatomy of the heart. Know the differences between the right and left side. Which ventricle is thicker? Why?
differences between the right and left side. Which ventricle is thicker? Why?
o Left is thicker bc has to pump to the whole body compared to right that just has to pump for pulmonary circuit.
- What are valves in the heart and what do they do?
o 4 valves in the heart that prevent backflow during pumping
Lub- tricuspid and mitral valves closing
Dub- aortic and pulmonary valves closing
- Think about what blood is entering each side (where does deoxygenated blood enter, what about blood that has traveled to the lungs?) and the movement.
Deoxygenated blood from the body enters your heart on the right through the superior and inferior vena cava. It is then pumped to your right ventricle which then pumps the blood to your lungs.
Pulmonary circuit
o Right side of the heart
o Carries oxygen poor blood to lungs for gas exchange and back to the heart.
Systemic circuit
o Left side of the heart
o Fully oxygenated blood from lungs is then send out to all tissues of the body and returns it to the heart.
Layers of the wall of the ventricle
Epicardium (epi=upon), Myocardium (myo=muscle), endocardium (endo=within)
epicardium
o Thin, external epithelium, the outermost layer of the heart.
o This is the visceral layer of the serous pericardium
o Slides without friction against the parietal layer of the serous pericardium.
Myocardium
o Thick, middle layer
o Cardiac muscle, the bulk of the heart.
o Contractile muscle cells (cardiac myocytes)
Endocardium
o Thin epithelial (endothelial) & innermost layer.
o Contracts blood in the chambers of the heart, but blood supply to the heart is through the coronary arteries.
- Where does the blood supply to the heart come from? Do cells that contact the blood in the chambers of the heart get nutrients and etc from that blood?
Endocardium contracts blood in the chambers of the heart, but blood supply to the heart is through the coronary arteries. No they get the nutrients from somewhere else.
- Do you know what the different kinds of heart cells are? The majority of the cells in the heart are what kind?
Contractile cells
* Compose 99% of heart cells.
Pacemaker cells
* Pacemaker cells compose only 1%