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Blood composition and function
carries nutrients, gas, waste, hormones around body
45% erythrocytes, <1% buffy coat: white blood cells and platelets, 55% plasma
- 90% water
- ions, sugars, amino acids, wastes (urea ammonia carbon dioxide), oxygen hormones and vitamins.
- three proteins:
- albumin- keeps water from diffusing out
- globulins- antibodies, blood proteins that carry ion, lipids and copper
- fibrinogen- protein and non protein molecules used in blood clotting
- biconcave, flat (large surface area), hugely numerous (~5million/mm3 = ~25 trillion/body).
- Other than water 97% hemoglobin (4 oxygen carrying polypeptides). No mitochondria or nucleus
- live 100-120 days (longer than most blood cells)
- ~4800-11,000/mm3. Only complete cells in formed elements.
- Can exit bloodstream and are part of immune system
- Granulocytes: neutrophils, eosinophils, Basophils
- agranulocytes: Lymphocytes and monocytes
Abundance order: N
- 60% of all White BC
- Nucleus has 2-6 lobes
- consume and destroy bacteria.
- Their granulocytes produce enzyme that destroys bacterial cell walls.
- 1-4% of Leukocytes
- bi-lobed nucleus
- "eosin-loving"- eosin is the acidic dye used for dying blood
- end allergic reactions by phagocytysing allergens and degrading histamine and other inflammatory responses
- 0.5% of WBC
- two-lobed nucleus
- "base-loving" dyed by the basic dye used to dying blood
- control later inflammatory responses, secrete histamine and other molecules
- similar to mast cell in connective tissue that mediate beginning stage of inflammation
- 20-45% of WBC and most important
- large spherical nucleus
- act in connective tissue against specific foreign molecules (antigens) and include B and T cells
- 4-8% of WBC and largest
- bent nucleus
- become macrophages in connective tissue
- Thrombocytes "clotting cells"
- plasa membrane enclose cytoplasm broken off from megakaryocytes
- at cut release products that attract other platelets, constrict blood vessels and induce inflammation.
- generate fibrin, which cause a clot
- (when undesired clotting: thrombus or embolus)
- occurs in the bone marrow. Makes ~100 billion new cells a day
- immature blood cells divide in the reticular connective tissue in bone marrow.
- Starts as bloom stem cell and differentiates into lymphoid stem cells or myeloid stem cell
Genesis of erythrocytes
- Committed cell is called proerythroblast
- collects iron and creates ribosomes which make more and more hemoglobin as it goes from:
- early erythroblast > late erythroblast > normoblast
- loses most organelles, then becomes reticulocyte, which is a young erythrocyte for 1 or 2 days before degrading ribsomes.
Formation of Leukocytes and Platlets
- Polycythemia- bone marrow cancer, too many RBC
- Anemia-hemoglobin is low causing fatigue
- sickle cell disease- defective hemoglobin causing reduced O2 levels, and difficulty fitting through capillaries
Leukemia- uncontrolled proliferation of WBC< depends on cell line. WBC crowd out red bone marrow
Thrombocytopenia; low platelets
Coverings of the heart (pericardium)
Heart is located in the mediastinum (between the lungs)
- 3 layers
- fibrous pericardium: the strong outer layer connected inferiorly to diaphragm and superiorly to blood vessels
- The serous pericardium consisting of the parietal and visceral layer which are continuous and has pericardial cavity in between
Layers of the heart wall
- 3 layers:
- epicardium- also the visceral layer of serous pericardium
- myocardium- made of cardiac muscle, arranged in bundles that contract the heart
- endocardium- endothelium on a thin layer of connective tissue that line the heart chambers and valves
Overview of Heart anatomy
- Left and right atriums and ventricles
- interatrial and interventricular septum - separating the sides of the heart
- coronary sulcus- separates atrium from ventricles
- anteror/posterior interventricular sulcus
- heart is placed obliquely with apex resting on the diaphragm
Right atrium of heart
- receives blood from the superior and inferior vena cava. (de-oxygenated blood)
- Right auricle ("little ear")-small flap on superior corner of atrium
- Internally has pectinate muscles "like teeth of a comb"
- Inferior and anteriorly the right atrioventricular (tricuspid) valve opens up to right ventricle
Right ventricle of heart
- most of the anterior surface of the heart.
- Inside of ventricle is marked by trabeculae carnae ("little beams of flesh")
- Thin strong bands, chordae tendinae, project from the papillary muscles to the tricuspid valve
- pumps blood to the pulmonary system via the pulmonary trunk
Left atrium and ventricle of heart
- Receives oxygenated blood from the pulmonary veins. Mostly smooth, Pectinate muscles only line the left auricle.
- pumps blood to the left ventricle via the mitral (left atrioventricular) valve.
- left ventricle forms apex of the heart, pumps blood into systemic circuit via the aortic valve and aorta. Has way thicker walls than right venticle or artiums
Pathway of blood
- inferior (body lower than diaphragm) superior (above diaphragm) vena cava and coronary sinus (walls of heart) > right atrium > tricuspid valve > right ventricle > pulmonary semilunar valve > pulmonary trunk > lungs > pulmonary veins (4) > left artium > mitral valve > left ventricle > aortic semilunar valve > aorta > (coronary arteries) systemic
Systole and diastole
- Systole - "contraction" of the atrium and ventricles
- diastole - "expansion" relaxation and filling of the heart chambers
atrioventricular valve function
- Prevent backflow from ventricles into atrium.
- when atrium is full and then systole, blood forces valves open. When ventricles are full, valves are forced shut and papillary muscles contract and the chordae tendinae keep the valves from opening into the atrium
the strength of the left ventricle can cause disorders in the mitral valve, allowing backflow into atrium. mitral valve prolapse
heart sounds are from valves closing
Semilunar valve functions
- valves that feed pulmonary artery and aorta prevent backflow into ventricles.
- pushed shut by backflow of blood into semilunar cusps of the valve flaps
Heart conducting system
- Cardiac muscle cells are not dependant on extrinsic factors to conduct an impulse and contract.
- The components, listed in sequential order, are the sinoatrial node (wall or right atrium)(pacemaker), atrioventricular node (inferior interatrial septium), atrioventricular bundle (interventricular septum), bundle branches (left and right), and Purkinje fibers (apex and ventricular walls).
- insulation by the fibrous skeleton prevents electric impulses from passing directly from artrium to ventricles
- Heart chambers sequentially contract in response to the impulse conduction path just listed.
Innervation of the heart
affected by the sympathetic and parasympathetic nerve fibers which can increase/decrease the rate and
Disorders of the Hear
- Coronary heart disease (CAD)- fatty deposits shrink arterial arterial, causing weakness, or if blocked causes myocardial infarction
- Heart failure-heart unable to keep up with demands of body (faulty valves), or heart enlarges and weakens
- conduction disorder-random stimulation of the heart
Embryonic development of the heart
Structure of most blood vessels
- 3 Tunics are layers of the blood vessels that surround the lumen, the central cavity
- tunic intima- inside layer in contact with lumen, flat endothelial layer, can have subendothelial layer
- tinica media- circular smooth muscle cells between elastin and collagen fibrils. Do vasoconstriction and vasodialation
- tinica externa- anchors the blood vessel to surrounding tissues. Connective tissue that adds support
- Thickest arteries around the heart. The Aorta and immediate connecting artiries (2.5-1 cm in diameter).
- Have lots of elastin that can store the potential energy of the influx of blood from the heart
Muscular (distributing) Arteries
- 1cm-.3mm in diameter
- have the largest porportional amount of tunica media to the lumen. Allows for regulation of blood to organs
- Just like external elastic lamina of tunica externa, dampens pressure of heart
- smallest arteries .3mm-10μm.
- tunica media only has 1-2 layers in tunic media. Size is mediated by smooth muscle and sympathetic nervous system indicating vasoconstriction
- smallest blood vessels, just large enough for blood vessels with diameter of 8-10μm.
- Single layer of endothelial layer with basement membrane
- allow for gas exchange, pick up waste, pickup hormones
- blood passes from artriole>metaartriole> thoroughfare channel >venules
- Thoroughfare channel has sphincters which control the feeding of capillary beds or not.
- single layer epithelium are partially connected with gap junctions with intercellular clefts.
- Transport includes (1) directly through cells, (2) intercellular clefts, (3) pinocytic vesicles and (4)through fenestrations in fenestrated capillaries
- Blood brain barrier has complete tight junctions and specialized active transport
- sinusoid capillaries allow for lots of transport, includind proteins (bone marrow)
- carry blood towards heart
- since blood pressure almost nonexistent after capillaries, veins are much thinner
- Venules>Veins>Vena Cava
- larger lumen carry 65% of blood at any given time. Veins have valves (from tunica interna) to counteract the lack of pressure. Muscles and movement help
- Varicose veins happens when valves fail and blood pools because of insifficient movement
- Hemorroids are varicose veins in the anal canal
Veins and arteries intersect, join and break apart allowing for alternative pathways for blood to flow if one is blocked. Blood can still be supplied to limb or organ
little veins and arteries break off from the main lumen to feed the blood vessels
/left pulmonary arteries
(make a "t" under aortic arch)>lobar arteries
(3 in right 2 in left lung) >arterioles and bronchi>air sacs>pulmonary veins
- much less pressure then in systemic circuit
leaves left ventricle (posterior to pulmonary trunk) curves over to from Aortic Arch
(posterior to manubrium). Three arteries that feed upper body leave Aortic Arch before descending aorta
(posterior to heart and decsends along midline). Thoracic aorta
and before diaphragm) becomes abdominal aorta
Arteries that feed upper limbs, neck and head
- 3 arteries branch from Aortic arch.
- 1) branchiocephalic trunk splits off to becomes right common carotid artery and right subclavian artery
- 2)left common carotid artery (common means it will split up)
- 3) left subclavian artery (mostly will go to left arm)
Common carotid arteries
vertebral arteries and thyrocervical and costocervial trunks
- feed most of the neck and head
- ascend in anterior neck, lateral to the trachea
- split into external and internal carotid artery
- Can be felt to find a pulse in the neck
- Vertebral arteries- branch from subclavian and supply parts of spine in neck and posterior cerebrum
- thyrocervical trunk and costocervial trunk-also subclavian, feed scalpular muscles and rest of neck
Arteries of upper extremity
- Runs laterally onto first rib and inferior to clavicle.
- Feed upper limb and changes name depending on location
- Subclavian> axillary artery (border of teres major)> Brachial artery (medial to humerus, deep to biceps)> radial (runs along medial side of brachioradialis, radial side, can feel pulse) and ulnar arteries (medial anterior forearm between superficial and deep flexors) >superfical and deep palmar arches
- internal thoracic artery - from subclavian artery feed posterior side of rib cage.
Arteries of the thorax
- Anterior thoracic wall from internal thoracic artery and anterior intercostal arteries
- Posterior thoracic wall from posterior intercostal arteries
- internal thoracic artery- paired, branches of from subclavian artery, lateral to the sternum, posterior side of ribcage
- Intercostal arteries: branch interthoracic artery and supply intercostal muscles. Some of posterior are from thoracic aorta
Arteries of the abdomen
- All from the abdominal aorta
- Three midline arteries for digestive and inner tube: celiac trunk, superior/inferior mesenteric arteries
- Paired branches for outer tube:adrenal gland, kidneys, gonads, abdominal wall
Inferior phrenic arteries
from T12 just inferior to aorta opening (hiatus) and supply inferior diapragm
- short, wide, unpaired, from T12 and emerges midventrally. (coelia="abdominal cavity"), three branches
- left gastric artery- (gaster="stomach") runs superiorly and left. Gives branches to esophagus and descends along the "J" of the stomach
- splenic artery- runs horizontal and left. Feeds spleen, pancreas and parts of stomach
- common hepatic artery-(hepat="liver") Runs right. Hepatic artery proper feeds liver and gallbladder. also branches to right gastric artery and gastroduodenal artery
Superior mesenteric artery
- large, unpaired, emerges midventrally from L1 posterior to pancreas. Inferior to celiac trunk.
- Runs inferiorly to enter mesentery (membrane that supports small intestine) Feeds majority of small intestine, and part of large intestine
- Lateral aortic branch (at L1). paired.
- supply the adrenal (suprarenal) glands, superior to kidneys.
- paired, from lateral aorta, right below suprarenal arteries.
- Supply kidneys ("renal") and remove nitrogenous waste
- paired. branch from L2. pass inferiorly to as testicular or ovarian arteries
Inferior mesenteric arteries
- unpaired artery, immediately before bifurcation of descending aorta. Supplies distal large intestine and rectum
Four pairs of branches on posterior aorta supply posterior abdominal wall
Middle (median) sacral artery
- thin, unpaired, from most inferior part of aorta.
- Descends to supply sacrum and coccyx
Common iliac arteries
- paired, from level L4, the aorta splits into the right and left common iliac arteries
- supply anterior abdominal wall, pelvic organs and lower limbs
- divides into internal and external
Arteries of pelvis and lower limb
- Common iliac arteries split into external and internal iliac arteries
- Internal-supplies pelvic arteries
- external supplies lower limb
Internal iliac artery
deep branch of common iliac artery. Supplies blood to pelvic walls, gluteal muscles (gluteal arteries), genital organs(internal pudendal artery), and adductor muscles of leg (obturator artery)
- From external iliac artery, after it passes midpoint of inguinal ligament.
- early break of deep femoral artery which supplies posterior thigh muscles.
- passes medial to femur, later to adductor muscles, goes through adductor hiatus and emerges posterior to femur to become popliteal artery.
- continuation of femoral artery, in the posterior knee (popliteal fossa). supplies knee joint.
- divides into the anterior and posterior tibial artery
Anterior and posterior tibial artery
Anterior- runs anterior leg through the interosseus membrane. At foot become dorsalis pedis artery and supplies dorsal foot
- posterior- runs down posterior medial leg, deep to soleus muscle. Branch into fibular artery. On foot, runs posterior to medial malleolus, supplies plantar side of foot
Systemic Veins (differences with arteries)
- Most run alongside arteries of the same name with a few exceptions
- -3 veins enter the heart, while one artery leaves it
- -All arteries lie deep and are protected, some veins are superficial
- -sometimes multiveins instead of one, called venous plexuses
- -veins from brain drain into dural sinuses, blood from digestive organs drain into hepatic portal system
Superior and inteferior venae cavae
- Superior vena cava- arises from union of left and right brachiocephalic veins (which are each formed by internal jugular vein and subclavian vein)
- Inferior vena cava- widest blood vessel in the body, collect all blood inferior to diaphragm, formed from common iliac veins
Veins of the head and neck
- Internal jugular vein- drains the dural sinuses which drain the brain. deep to sternocleidomastoid, lateral to carotid arteries. Dumps into brachicephalic vein
- External jugular vein- drains posterior, lateral scalp and part of face. Superficial to sternocleidomastoid. empties into subclavian vein
- Vertebral veins-only drain cervical vertebrae, spinal cord and superior neck. goes trough transverse foramina as venous plexus. Joins braichiocephalic vein
Veins of upper limb
Deep veins are same as arteries. Radial
vessels empty into brachial
which becomes axially
to become subclavian
- superficial veins-larger than deep veins. start as dorsal venous network on dorsal hand. Empty to cephalic vein (anteriorlateral side of arm to join axillary vein). Basilic vein- anterior and posterior medial side of arm. (enters brachial vein)
- median cubital vein- connects basilic and cephalic veins in cubital fossa
Veins of the thorax
- Intercostal veins, other thoracic veins, hemiazygos and accesory hemiazygos veins all drain into the Azygos vein which drains into the superiod vena cava
Veins of the abdomen
- Drain into inferior vena cava and almost all have names corresponding to arteries.
- Lumbar, gonadal (asymetric: left gonadal drain into renal vein), renal veins, suprarenal veins, hepatic veins.
- Via hepatic portal: superior mesenteric, splenic, inferior mesenteric, gastric veins (all drain into liver and then hepatic vein to inferior vena cava)
Hepatic portal system
- Veins from digestive organs carry nutrients to liver via hepatic pootal system for processing and storage (to breakdown toxins). Travel via hepatic portal vein.
- Superior mesenteric vein- small intestine and part of large intestine
- splenic vein- spleen isnt digestive, but microbes that excape spleen get broken down in liver
- inferior mesenteric vein- distal large intestine and superior rectum
- Gastric veins- join hepatic protal vein closer to liver
Veins of pelvis and lower limbs
deep veins: share names of arteries. plantar veins, posterior
veins > popliteal
vein > femoral
vein (+deep femoral vein)> external
iliac vein (=internal iliac vein)>common iliac vein
- superficial veins: great sapheneous veins run from dorsal venous arch up medial leg to femoral vein. small sapheneous vein, runs posterior leg to popliteal vein. Form anastomoses
disorders of blood vessels
- Aneurysm-outpocket of artery from gradual weakening of the vessel, rupture is dangerous
- deep vein thrombosis of lower limb- clot in vein dislodges and become embolism which blocks pulmonary artery. From slow blood, treating with anticlotting agents
- venous disease-insufficient drainage of veins, faulty valves, lead to tissue damage
- microangiopathy of diabetes- thick leaky capillaries from deposit of glycoproteins (too much blood sugar).
- arteriovenous malformation-lack of capillary bed, too much arterial pressure for veins to handle
- Blocking of arteries, increased ridigity, hypertension, decreased gas and waste exchange.
- Prevent by removing blockages and taking blood thinners
- blood vessels are in place by third month. Direction and flow is similar to adult except gas exchange occurs through the placenta via the umbilical chord.
- Blood is shunted away from pulmonary system because it is not functioning
vessels to and from placenta and fetal heart shunts
- umbilical arteries carry blood to placenta to pick up nutrients and oxygen.
- Umbilical veins returns blood to fetus, some to the portal vein and some to the ductus venosus. Then all goes to the fetal heart.
- In fetal heart, blood is shunted from the pulmonary circuit via the foramen ovale (in interatrial septum) and ductus arterios (from pulmonary trunk to aortic arch)
The lymphatic system
Capillaries are surrounded by loose connective tissue that collect more blood than leave.
Lymphatic system collects excess blood and returns it to heart. returns leaked proteins to heart and carry absorbed fat from intestine to the blood through lacteals. Also fight disease.
- System is only one way. Lymphatic capillaries>lymphatic collecting vessels (have lymph nodes along the way)>lymph trunks>lymph ducts>veins in root of neck
- near blood capillaries. Are single layer endothelium with flaplike minivavles that are highly permeable to plasma, proteins, pathogens. Once inside tissue fluid becomes lymph.
- Absent from bone, teeth, bone marrow and CNS where excess flows into CSF to superior sagittal sinus.
Lymphatic collecting vessels
- narrow and delicate with same layers as veins except much thinner and weaker. Use more valves and bulging nodes to keep lymph moving. (also muscles, pulsing arteries, limb movements, and weak tunica media help). Edema can occur is standing without moving.
- Lymphangiography allows for viewing lymphatic collecting vessels
- clean lymph of pathogens. 500 nodes in the human body (1-25mm in diameter).
- node is covered by fibrous capsule of trabeculae, "beams", which also divide lymph into compartments. Lymph enters through afferent lymphatic vessels and pass through lymph sinuses (subscalpular, cortical and medullary), reticular network, macrophages and then pass through hilum to efferent lymphatic vessels.
- all pathogens are killed through because of many lymph nodes
- can get swollen from pathogens that arent killed yet. Swollen but not painful lymph nodes is a sign of cancer in lymph nodes
- Drain large areas of the body and can be seen in dissection. Lumbar (paired), intestinal (unpaired), bronchomediastinal (paired), subclavian (paired) and jugular trunks (paired).
- Trunks drain into ducts.
- Thoracic duct is present in all individuals. Has cisterna chyli which is saclike chamber at base. Located mid-thoracic and ventral to spinal cord. Drains lymph from lower body and left upper body into left subclavian vein.
- Right lymphatic duct (20% of people) otherwise trunk open directly into neck veins.
The immune system
- Targets specific pathogens.
- Lymphoctes, lymphoid tissue, and lymphoid organs (spleen, thymus, tonsils, lymphoid nodules in small intestine and appendix)
- Target specific antigens
- Cytotoxic, killer, CD8+ T lymphocytes- bind to antigens on eukaryotic cells that have been infected or are foreign and initiate apoptosis.
- B cells become plasma cells which secrete antibodies. These tag cells (mostly bacteria and toxins) for destruction
- NK cells- detect non self antigens and foreign sugars and lyse them..
- B cells mature in bone marrow. T cells mature in Thymus. Develop immunocompetence
- Released to connective tissue and activated when presented with antigen.
- Effector lymphocytes are short lived and respond to pathogen. Plasma cells. helper (CD4) T cells help activation and recruit innate immune system by secreting cytokines.
- memory cells.
- specialized connective tissue that fights infection. Has lymphoid follicles/nodules, which have germinal centers of dividing lympocytes.
- 2 locations
- 1)mucosa-associated lymphoid tissue (MALT)-mucous membranes of digestive, respiratory, urinary and reproductive tracts.
- 2)All lymphoid organs
- In upper thorax, posterior to sternum. Grows in size until adolescence and then slowly atrophies. Creates immunocompetent T-cells
- Contains lobules each which contains outer cortex (packed with cells) and inner medulla (which has thymic (Hassall's) corpucles which are collections of degenerating reticular cells.
- Has blood-thymus barrier and develops self-tolerance.
- where lymphatic and immune system intersect
- have external cortex with B cells and inner medulla with T cells, and Helper t cells that activate B cells.
- largest lymphoid organ. superior left quadrant of abdomen, posterior to stomach.
- Removes blood born antigens and aged/defective blood cells.
- Major arteries of spleen are central arteries are surrounded by white pulp which removes antigens from blood. (immune function).
- Surrounding white pulp is red pulp which has 1) venous sinuses- blood sinusoids from distal arteries. and 2)splenic cords- reticular connective tissue with macrophages that destroy red blood cells
- Palatine tonsils (most likely to be removed), lingual, pharyeal, tubal tonsils.
- arranged in a ring around the entrance to pharynx. They are MALT, and packed with lympocytes and have crypts which gather bacteria and particulate matter.
Aggregated lymphoid nodules and appendix
- Aggregated lymphoid nodules (Peyer's patches) are in ileum of small intestine are 40 lined up together.
- appendix a tubular shootoff of cecum (large intestine). These kill microorganisms and sample large amounts creating memory lymphocytes.
Disorders of lymphatic system
- Chylothorax- leakage of fatty lymph, chyle, from thoracic duct into thorax. Decrease fat and volume in blood, too much lymph in pleural cavity.
- Lymphangitis- when lymphatic vessel gets swollen and infected
- mononucleosis- Epstein-Barr virus, when T cells are activated to destroy infected B cells
- Hogkin's disease-malignant lymph nodes, seem to be caused by malignant lymphocytes
- Non-hogkin's lymphoma- all other lymph cancers, very dangerous, cancerous B or T cells
- are small and discontinuous.
- Pure endocrine organs: pituitary gland (base of brain), pineal gland (roof of diencephalon), thyroid and parathyroid glands (neck), Adrenal gland (above kidneys)
- other endocrine organs: pancreas, thymus, gonads, and hypothalamus
Classes of hormones
- Amino acid-based hormones- modified amino acids (amines), peptides,and proteins.
- Steroids- lipid molecules from cholestrol
Basic hormone action
- Molecular triggers, do not have coded action.
- circulate through the bloodstream encountering all tissues, but only affect target cells.
control of hormone secretion
- Three major types of stimuli
- humoral stimuli- secretion based on changing level of ions or nutirents in blood.
- neural stimuli-nervous system triggers release.
- hormonal stimuli-secretion based on hormones received from other endocrine glands.
- also controlled by postive or negative feedback loops
Pituitary gland (hypophysis)
- connected to hypothalamus via the infundibulum (control of hormone release by hypothalamus)
- anterior pituitary gland (adenohypophysis)- made of gland tissue. pars distalis, pars intermedia and pars tuberalis
- neurohypophysis- (made of nervous tissue) pars nervousa, infundibular stalk, median eminence (attached to hypothalamus)
- secretes FLAT PGM
- Follicle stimulating hormone, Lutineizing hormone, Adrenocorticotropic hormone, Thyroid-stimulating hormone, Prolactin, growth hormone, melanocyte-stimulating hormone
- oxytocin and anti-diuretic hormone
Growth hormone (GH)
- Also called somatropic hormone (SH) "body changing".
- Affects the entire body. promoting growth of epiphyseal plate.
- From the adenohypopysis (anterior pituitary gland) specifically somatotropic cells.
- stimulates manufacture of milk from breasts
- made from mammotropic cells. Made in Adenohypophysis
Thyroid stimulating hormone (TSH)
- Made in adenohypophysis by thyrotropic cells
- Prompts thyroid to secrete Thyroid hormone which is both thyroxine (T4) and triodothyronine (T3) which increase the metabolic rate and growth
Adrenocorticotropic hormone (ACTH)
- Made in adenohypophysis by corticotropic cells in response to stress.
- "Adrenal cortex changing"
- stimulates adrenal cortex to secrete glucocorticoid (main one is cortisol) which is anti-inflammatory and anti-stress compound
Melanocyte-stimulating hormone (MSH)
- Made in adenohypophysis by Corticotropic cells.
- Stimulates melanocytes to produce melanin to darken skin in response to UV rays.
Gonadotropins: follicle stimulating (FSH) and luteinizing hormone (LH)
- Made in adenohypophysis by gonadotropic cells
- They stimulate maturation of sex cells.
- In females, FSH and LH stimulate maturation of egg containing ovarian follicles, and secretion of androgens, estrogen and progesterone
- in middle of menstrual cycle large amount of LH induces ovulating
- In males, LH signals secretion of testosterone and FSH stimulates stimulates maturation of sperm cells
Tropic v nontropic hormones
- Tropic hormones affect a target organ to release another hormone.
- nontropic hormones act directly on nonendocrine target tissues and cells
- Stores and releases two hormones that are made in the hypothalamus
- antidiuretic hormone (ADH)- Vasopressin, cause reabsorption of water by collecting ducts and distal tubules of kidney.
- oxytocin- induces contraction of smooth muscles of reproductive organs. play a role in human socializing (cuddling, grooming and bonding)
- Butteyfly shaped, two lateral lobes and isthmus.
- Thyroid hormone- thyroxine and triiodothyronine. increase metabolic rate and growth
- calcintonin- lowers Ca2+ levels of the blood. slows osteoclast activity.
- on posterior surface of thyroid gland.
- Chief cells produce parathyroid hormone
- Parathyroid hormone (PTH)- increases blood Ca2+ concentration. stimulate osteoclasts and decrease secretion of Ca2+ in kidneys, activates vitamin D (uptake of Ca2+ in intestines)
on top of kidneys. Fed by 60 seuprarenal arteries
- two endocrine glands: adrenal medulla (part of sympathetic nervous system) and adrenal cortex (bulk of gland)
- both secrete hormones associated with danger, stress and terror
- Autonomic immune system
- chromaffin cell secrete epineprine and norepinephrine. They increase blood pressure and prepare body for stressful, physical activity.
- secretes lipid based hormones.
- Made of zonas glomeulosa, fasciculata, and reticularis
- Secrete corticosteroids- mineral and gluco corticoids
- Mineralocorticoid- aldosterone, in response to decreased blood pressure. prompts reuptake of Na+ into the blood (zone glomerulosa)
- glucocorticoids- cortisol anti-inflammatory and anti-stress compound. Keep blood sugar level high enough for brain.
Structure of steroid-secreting cells
Have lots of smooth ER and no secretory granules
- Small pine-cone shaped on roof of diencephalon.
- Secretes melatonin which regulates circadian rhythm
- Exocrine cells secrete digestive enzymes
- Endocrine cells are called pancreatic islets/islets of Langerhans.
- Alpha cells secerete glucagon which signals liver to secrete glucose, when blood sugar is low. Beta cells secrete insulin which signal cells to uptake glucose, lowering blood sugar levels
- Delta cells secrete somatostatin which inhibits secretion of glucagon and insulin
Thymus (as endocrine organ)
- T-lympocyte production is stimulated by thymic hormones, which are peptide molecules.
- Thymopoietin and thymosins
- In testes, interstitial cells secrete andogens, mostly testosterone, which produce secondary male characteristics.
- In females androgens, estrogen and progesterone maintain female secondary characteristics and signal uterus to prepare for pregnancy.
Other endocrine structures
- heart- atrial natriuretic peptide
- Gastrointestinal tract- diffuse neuroendocrine system
- Placenta-human chronic gonadotropin influences pregnancy
- Kidneys-renin signals adrenal glands
- Skin-vitamin D signals intestine to absorb Ca2+ from diet
- gigantism- overproduction of GH in children, can cause acromegaly
- pituitary dwarfs- underproduction of GH
- diabetes insipidus- pars nervousa doesnt secrete enough antidiuretic hormone (ADH), excess urine
Disorders of pancreas:diabetes mellitus
- Diabetes mellitus: when body doesny secrete enough insulin, or cells are unreactive
- Type 1 diabetes (insulin-dependent): T-cells destroy β-cells and insulin isnt secreted. High lipid levels in blood and excess blood in tissue fluids cause problems
- Type 2 Diabetes: cells have reduced sensitivity to insulin. Treated through diet and excercise changes
disorders of thyroid gland
- Graves' disease: over stimulation of thyroid hormone leading to elevated metabolic rate. eyes popping out of head
- Adult hypothyroidism: Less TH, lower metabolic rate, less energy
- endemic goiter: insifficient iodine intake leads to less TH in system
Disorders of adrenal cortex
- Cushing's disease: hypersecretion of glucocorticoid hormones. High glucose blood levels, loss of proteins from muscles.
- addison's disease: deficiency of gluco and mineralocorticoids. blood and Na blood levels drop, severe dehydration and low blood pressure