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20 Cards in this Set
- Front
- Back
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Adrenal Gland?
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(aka suprarenal glands) are endocrine glands that sit atop the kidneys; in humans, the right suprarenal gland is triangular shaped, while the left suprarenal gland is semilunar shaped, weight about 7-10gm.
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Adrenal Gland Fxn?
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Release Hormone in response to stress, i.e, Catecholamines & Cortisol.
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Anatomy of the Adrenal Gland.
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The adrenal glands are located in the retroperitoneum superior to the kidneys, bilaterally.
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The outer adrenal cortex and the inner medulla:
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The cortex mainly produces cortisol, aldosterone and androgens, while the medulla chiefly produces epinephrine and norepinephrine.
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Cortex consist of :
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Zona glomerulosa (outer):outermost layer the main site for production of mineralocorticoids, mainly aldosterone, which is largely responsible for the long-term regulation of blood pressure.Aldosterone's effects are on the distal convoluted tubule and collecting duct of the kidney where is causes increased reabsorption of sodium and increased excretion of both potassium (by principal cells) and hydrogen ions (by intercalated cells of the collecting duct). Sodium retention is also a response of the salivary ducts, distal colon, and sweat glands to aldosterone receptor stimulation. The major stimulus to produce aldosterone is angiotensin II while ACTH from the pituitary only produces a transient effect. Angiotensin is stimulated by the juxtaglomerular cells when renal blood pressure drops below 90 mmHg.[4]
Zona fasciculata:Situated between the glomerulosa and reticularis, the zona fasciculata is responsible for producing glucocorticoids. Zona reticularis:The inner most cortical layer, the zona reticularis produces androgens, mainly dehydroepiandrosterone (DHEA) DHEA sulfate (DHEA-S), and androstenedione (the precursor to testosterone) in humans. |
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Medulla produces what?
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The core of the adrenal gland, and is surrounded by the adrenal cortex. It secretes approximately 20% norepinephrine and 80% epinephrine.
The adrenal medulla receives input from the sympathetic nervous system through preganglionic fibers originating in the thoracic spinal cord from T5–T11.Because it is innervated by preganglionic nerve fibers, the adrenal medulla can be considered as a specialized sympathetic ganglion. Cortisol also promotes epinephrine synthesis in the medulla via upregulation of phenylethanolamine N-methyltransferase (PNMT), thereby increasing epinephrine synthesis and secretion. |
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Blood supply of the Adrenal Glands:
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The superior suprarenal artery is provided by the inferior phrenic artery
The middle suprarenal artery is provided by the abdominal aorta The inferior suprarenal artery is provided by the renal artery Venous drainage of the adrenal glands is achieved via the suprarenal veins: The right suprarenal vein drains into the inferior vena cava The left suprarenal vein drains into the left renal vein or the left inferior phrenic vein. |
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Misc about the adrenal glands:
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The adrenal glands and the thyroid gland are the organs that have the greatest blood supply per gram of tissue. Up to 60 arterioles may enter each adrenal gland.[6] This may be one of the reasons lung cancer commonly metastasizes to the adrenals
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Difference btw Cardiac and Skeletal Muscles:
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Cardiac muscle cells may be branched instead of linear and longitudinal compared to the Skeletal Muscle.
Fewer T-tubules in the Cardiac muscle, which are larger, broader and run along the Z-Discs. Intercalated Disc which connect single cardiac myocytes to an electrochemical syncytium, aid and support the rapid spread of action potentials and the synchronized contraction of the myocardium. Intercalated Disc consist of 3-Cell types: fascia adherens, macula adherens and gap junctions. Cardia Muscle extracellular calcium ions through L-type calcium channels sustains the depolarization of cardiac muscle cells for a longer duration. |
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Cells that produces Melanin:
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Melanocytes: are melanin-producing cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear, meninges, bones, and heart. Melanin is a pigment that is responsible primarily for the color of skin.
The production of melanin is also initiated by ACTH (an adrenocorticotropic hormone). Vitamin D metabolites, retinoids, melanocyte-stimulating hormone, forskolin, cholera toxin, isobutylmethylxanthine, diacylglycerol analogues, and UV irradiation all trigger melanogenesis and, in turn, pigmentation. Also producing chronic diseases when UV Rays hit open sores. |
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Rate limiting enzyme for fat synthesis:
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HMA reductase.
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Fatty acid synthesis:
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Controlled by Insulin via the stimulation of pyruvate dehydrogenase to form Acetyl CoA (B5), while and acetyl-CoA carboxylase (ACC), which forms malonyl-CoA from acetyl-CoA acts as a substrate for fatty acids synthesis.
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PDH dephosphorylation:
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Pyruvate dehydrogenase dephosphorylation is increased with the release of insulin,the dephosphorylated form is more active.
insulin does not activate adenylate cyclase. Epinephrine via the beta adrenergic receptor and glucagon via its receptor activate adenylate cyclase, increasing cAMP levels and PKA activity. Insulin activates cAMP phosphodiesterase, which breaks down cAMP. This leads to a decrease in cAMP levels and therefore a decrease in PKA activity. With regard to Pyruvate dehydrogenase, this enzyme is inhibited when phosphorylated. Insulin stimulates the activity of pyruvate dehydrogenase phosphatase. This enzyme removes the phosphate from pyruvate dehydrogenase, allowing for conversion of pyruvate to acetyl-CoA. This mechanism leads to the increased rate of catalysis of this enzyme, so increases the levels of acetyl-CoA. Increased levels of acetyl-CoA will increase the flux through not only the fat synthesis pathway but also the citric acid cycle. |
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Acetyl-CoA carboxylase:
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Insulin affects ACC in a similar way to PDH. It leads to its dephosphorylation which activates the enzyme. Glucagon has an antagonistic effect and increases phosphorylation, deactivation, thereby inhibiting ACC and slowing fat synthesis.
Affecting ACC affects the rate of acetyl-CoA conversion to malonyl-CoA. Increased malonyl-CoA level pushes the equilibrium over to increase production of fatty acids through biosynthesis. Long chain fatty acids are negative allosteric regulators of ACC and so when the cell has sufficient long chain fatty acids, they will eventually inhibit ACC activity and stop fatty acid synthesis. AMP and ATP concentrations of the cell act as a measure of the ATP needs of a cell and as ATP levels get low it activates the ATP synthetase which in turn phosphorylates ACC. When ATP is depleted, there is a rise in 5'AMP. This rise activates AMP-activated protein kinase, which phosphorylates ACC, thereby inhibits fat synthesis. This is a useful way to ensure that glucose is not diverted down a storage pathway in times when energy levels are low. ACC is also activated by citrate. This means that, when there is abundant acetyl-CoA in the cell cytoplasm for fat synthesis, it proceeds at an appropriate rate. Note: Research now shows that glucose metabolism (exact metabolite to be determined), aside from insulin's influence on lipogenic enzyme genes, can induce the gene products for liver's pyruvate kinase, acetyl-CoA carboxylase, and fatty acid synthase. These genes are induced by the transcription factors ChREBP/Mlx via high blood glucose levels[3] and presently unknown signaling events. Insulin induction is due to SREBP-1c, which is also involved in cholesterol metabolism. |
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Internal Jugular Vein:
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On both sides and at the base of the brain, the inferior petrosal sinus and the sigmoid sinus join to form the internal jugular vein. The internal jugular vein begins in the posterior compartment of the jugular foramen, at the base of the skull.
It is somewhat dilated at its origin, and this dilatation is called the superior bulb. It also has a common trunk into which drains the anterior branch of the retromandibular vein, the facial vein, and the lingual vein. It runs down the side of the neck in a vertical direction, being at one end lateral to the internal carotid artery, and then lateral to the common carotid, and at the root of the neck, it unites with the subclavian vein to form the brachiocephalic vein (innominate vein); a little above its termination is a second dilatation, the inferior bulb. Above, it lies upon the rectus capitis lateralis, behind the internal carotid artery and the nerves passing through the jugular foramen; lower down, the vein and artery lie upon the same plane, the glossopharyngeal and hypoglossal nerves passing forward between them; the vagus descends between and behind the vein and the artery in the same sheath (the carotid sheath), and the accessory runs obliquely backward, superficial or deep to the vein. At the root of the neck, the right internal jugular vein is a little distance from the common carotid artery, and crosses the first part of the subclavian artery, while the left internal jugular vein usually overlaps the common carotid artery. The left vein is generally smaller than the right, and each contains a pair of valves, which are placed about 2.5 cm above the termination of the vessel. The jugular veins are relatively superficial and not protected by tissues such as bone or cartilage. This makes them susceptible to damage. Due to the large volumes of blood that flow though the jugular veins, damage to the jugulars can quickly cause significant blood loss, which can lead to hypovolæmic shock and then death if not treated. It should also be noted that cuts or abrasions in the skin near the jugular vein will bleed longer and more profusely (i.e from chewing tobacco or shaving accidents). Since 95% of the body's blood passes through this vein, it takes on average about 30 minutes to fully stop a shaving abrasion on the face |
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•When superficial temporal vein and Maxillary vein meet they give rise to:
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Retromandibular Vein:formed by the union of the superficial temporal and maxillary veins, descends in the substance of the parotid gland, superficial to the external carotid artery but beneath the facial nerve, between the ramus of the mandible and the sternocleidomastoideus muscle.
It divides into two branches: an anterior, which passes forward and unites with the anterior facial vein to form the common facial vein. a posterior, which is joined by the posterior auricular vein and becomes the external jugular vein. |
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Flexors of the shoulder?
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Coracobrachialis(Musculocutaneous Nerve)
Deltoid (Axillary nerve) Pectoralis Major (Med & Lat pectoral nerves). |
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Extensors of the shoulder?
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Teres Major (Lower Subscapular)
Latissimus Dorsi (Thoracodorsal nerve) Deltoid Posterior head (Axillary Nerve) |
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Abductors of the shoulder?
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Deltoid middle segment
(Axillary Nerve) Supraspinatus ( Suprascapular nerve) |
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Adductors of the shoulder?
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Teres Major
(lower subscapular nerve) Latissimus Dorsi (Thoracodorsal nerve) Pectoralis Major (Med & Lat pectoral nerves). Teres Minor (Axillary nerve) |
