anatomy exam 4

connective tissue definition

tissue that connects, supports, binds, or separates other tissues or organs

why is blood classified as a connective tissue?

classified as a specialized fluid connective tissue because it consists of living cells suspended in a non living fluid matrix, links all body systems together, transporting nutrients, gases, and wastes

blood layers: erythrocytes

heaviest, fall to the bottom due to iron content, 40-45% of blood makeup

blood layers: buffy ccoat

makes up less than one percent of blood, contains leukocytes and platelets

blood layers: plasma

makes up 55% of blood, 90% water, also contains plasma proteins and small solutes

plasma proteins: albumin

maintains osmotic pressure, draws water into vessels, made by liver

plasma proteins: immune proteins

regulate the immune response

plasma proteins: transport proteins

carry hydrophobic substances, amphipathic, example LDL for cholesterol

plasma proteins: clotting proteins

regulate coagulation

plasma solutes can include (~1%):

glucose, amino acids, electrolytes like na, k, and ca, gases, and waste (urea)

erythrocyte structure

biconcave disc, 7.5 microns diameter, 2.5 thick, flexible, fold in half to pass 5 micron capillaries, amytotic and anucleate, little to no mitochondria, live roughly 120 days

red blood cell production

2-3 mill made per second, 5 mill per microliter, 25 tril total in the body

hemoglobin structure and function

4 chains, 2 alpha 2 beta, and four heme groups, each binds 4 oxygen molecules

hemoglobin regulation

allosteric regulation by oxygen, borh effect where lower pH leads to lower oxygen binding

whats the pH range of the blood?

7.35-7.45

iron handling in blood

50% of body iron in hemoglobin, the rest found in ferritin for storage, transferrin for transport, and lactoferrin for limiting bacterial growth

RBC production factors: folate

crucial water soluble nutrient essential for red blood cell production, DNA synthesis, and cell division, found in leafy greens

RBC production factors: vitamin B12

essential for red blood cell production, acting as a cofactor for DNA synthesis and maturation of erythroblasts in the bone marrow, works with folate

RBC production factors: intrinsic factor

needed for B12 absorbption

where are red blood cells made?

in red bone marrow stem cells in spongy bones, process called hematopoiesis

anemia

insufficient supply of healthy red blood cells or hemoglobin, restricts the bodys ability to carry oxygen to tissues and organs

anemia type 1.1: iron deficiency

most common, commonly caused by blood loss or diet, mainly females

anemia type 1.2: vitamin B12 deficiency

pernicious anemia, lack of intrinsic factor, requires injections, also dietery

anemia type 1.3: folate deficiency

poor diet, treated with supplements

anemia types: aplastic anemia

bone marrow failure due to toxic drugs or cancer

anemia types: hemorrhagic anemia

blood loss from the body leading to iron deficiency

anemia types: erythropoietin deficiency

inadequate secretion of erythropoietin in kidney disease

anemia types: hemolytic disease

excessive destruction of erythrocytes, such as in diseases like sickle cell or drug induced

hematopoiesis

formation of blood cells in red bone marrow, epiphysis, from stem cells, regulated by erythropoietin from kidneys, triggered by low oxygen

RBC production stage 1: hematopoietic stem cell

cell may become any type of formed element, multipotent

RBC production stage 2: erythrocyte-CFU

cell is now committed to becoming an erythrocyte

RBC production stage 3: proerythroblast

step requires the hormone erythropoietin from kidneys

RBC production stage 4: early erythroblast

hemoglobin is synthesized rapidly

RBC production stage 5: late erythroblast

nucleus shrinks and is ejected with other organelles (they broke up)

RBC production stage 6: reticulocyte

remaining organelles are ejected, cell enters bloodstream, immature red blood cell

RBC production stage 7: erythrocyte

cell is now mature and performs normal blood cell functions

erythrocyte death

takes place in the spleen, trapped in sinusoids and digested by macrophages, amino acids and iron reused, iron by transferrin, bilirubin brought to liver for bile excretion

erythrocytes in sickle cell disease

an inherited disorder causing red blood cells to become rigid, sticky, and sickle shaped due to abnormal hemoglobin, clump together and block blood flow

leukopoiesis

process of producing white blood cells in the bone marrow, driven by hematopoietic stem cells to maintain immune defense

hemostasis

multi stage physiological process that stops bleeding after blood vessel injury, preventing excessive blood loss

hemostasis 1: vascular spasm

Immediate narrowing of the damaged vessel to reduce blood flow, exact signaling mechanism not know, but is triggered by vessel damage

hemostasis 2: platelet plug

platelets are attracted to the site of injury, begin to stick together and damaged area due to vWF, which activates them, chemicals attract more to the site, thromboxane A2, serotonin, ADP

what are platelets?

thrombocytes, fragments of megakaryocytes, small, numerous, able to respond immediately

adhesion of platelets

platelets stick to damaged vessel wall

aggregation of platelets

platelets stick to one another

hemostasis 4: clot retraction

wound edges are brought together, pushing the clot out of the area, serum squeezed out of clot

what is serum?

plasma without clotting proteins

hemostasis 5: thrombolysis

endothelial cells release tPA and activates plasminogen, which degrades fibrin and dissolves the clot

Rh factor

identified in rhesus monkeys, 85% of individuals are rh positive and contain the rh antigen

pregnancy issue Rh factor

Rh negative mother conceiving Rh positive child, first pregnancy is usually fine, the following increases risks as mother develops anti rh antibodies, which can cross placenta and agglutinate fetal blood cells

agglutination

clumping of red blood cells when antigens on the cells bind to corresponding antibodies in the plasma, leads to hemolysis

universal donor

blood type O negative, lacks a, b, and rh antigens

universal recipient

blood type AB positive, lacks a, b and rh antibodies

lymphatic system function overview

maintain fluid balance by returning excess tissue fluid to the bloodstream, support the immune system by producing and transporting white blood cells to fight infections, and absorb fats and nutrients from the digestive system

lymphatic organs

spleen, thymus, tonsils, MALT, lymph nodes,

spleen

upper left quadrant, contains red pulp, primary site of erythrocyte destruction by macrophages in sinusoids, and white pulp, containing white blood cells

splenomegaly

enlargement of the spleen, seen in some platelet disorders, vulnerable to injury

thymus

located posterior to sternum, anterior to heart, atrophies in adults and replaced with adipose and connective tissue, site of t cell maturation

t cell maturation

born in the bone marrow, but travel to the thymus to mature and become functional, most made in childhood, thymus shrinks and becomes less active in adulthood

tonsils

cluster of lymphatic tissue, includes pharyngeal/adenoids, palatine, and lingual tonsils, can swell and impede breathing and swallowing

MALT, mucosa-associated lymphoid tissue

lymphatic tissue found throughout mucous membranes such as intestines

peyer patches

clusters of malt in the small intestines, also called gut associated lymphoid tissue

appendix (vermiform appendix)

a small, finger like projection with a high concentration of MALT, often considered vestigial, can become inflammed

lymph nodes

clustered in specific regions, cervical, axillary, inguinal, mesenteric, enlarge when fighting infection due to increased immune cell activity

afferent lymphatic vessels

bring lymph to the node

efferent lymphatic vessels

carry lymph out of the node at the hilum

lymph node structure

contains valves to ensure one way flow, outer capsule, underlying cortex, and inner medulla, contains lymphoid follicles in cortex, site of lymphocyte proliferation, highly vascularized

what is more abundant in the spleen: red pulp or white pulp

red pulp, about 85%

pathways for activation of the complement system

classical, lectin, and alternative pathway

classical pathway

activated when complement proteins bind to an antibody-antigen complex

the complement system

a system of over 30 plasma proteins that complement or assist other immune responses in destroying pathogenic substances

where are plasma proteins made?

in the liver

edema

fluid buildup in interstitial spaces, either pitting, causing dips in skin, or non pitting

lymphatic primary function one: alternate venous system

collects excess interstitial fluid and returns it to the cardiovascular system

lymphatic primary function two: immune surveillance

checks lymph and fluid for pathogens and foreign antigens

where are lymph nodes and vessels found?

everywhere except the brain and spinal cord

glymphatic system

in the brain and spinal cord, regulated by glial cells, return fluid to dural venous sinuses

lymphatic capillaries

embedded in capillary beds, fluid moves from the interstitial space into lymphatic capillaries by hydrostatic pressure, aided by skeletal muscle contraction

lymph

fluid that has entered a lymphatic capillary

what kind of system is the lymphatic system?

an open system, fluid moves in one direction through one set of vessels

how does liver disease cause edema?

reduced albumin production results in decreased oncotic pressure, which decreases the amount of fluid drawn back into capillaries, preventing lymph return

right lymphatic trunk

drains lymph from the right side of the head and neck, right arm, and right thoracic cavity, emptying into the right subclavian vein

thoracic duct

drains lymph from the rest of the body, left jugular, subclavian, and brachiomediastinal trunks, lower extremities, abdominal and pelvic

cisterna chyli

a widened confluence where the right lumbar, left lumbar, and intestinal trunks merge, forming the beginning of the thoracic duct, empties into left subclavian

why do lymphatic vessels exist?

not all fluid returns to blood capillaries, extra fluid must be picked up, becoming lymph

how does hydrostatic pressure work in the lymphatic system?

primary force pushing fluid out of capill

how does osmotic pressure work in the lymphatic system?

draws water from tissues back into blood capillaries, driven by proteins like albumin, lymph does the rest

microscopic structure of lymphatic organs

composed of reticular connective tissue, reticular fibers and cells, contains immune cells such as macrophages, B and T lymphocytes, dendritic cells

lectin pathway

activated when lectin proteins bind to carbohydrates on microbial surfaces

alternative pathway

spontaneous, continuous cleavage of C3 into C3B and C3A, tick over response, engine idling, constant generation

C3B activation effect: cell lysis

activates C5B, forms membrane attack complexes that create pores in the membranes of pathogens, leading to cell death

C3B activation effect: enhanced inflammation

activates C5B, which binds with C3A and increases basophil activity, leading to more histamine production

C3B activation effect: virus neutralization

C3B binds directly to virus, preventing them from infecting cells

C3B activation effect: enhanced phagocytosis (opsonization)

C3B coats pathogens, making them more visible and appealing for phagocytic cells like macrophages

C3B activation effect: clearance of immune complexes

C3B aids in the removal of antibody-antigen complexes

innate response to cellular injury

inflammatory response, non specific, destroys both pathogens and own cells

classic inflammation signs

redness, swelling, heat

inflammatory response step one

begins when damaged cells and mast cells release inflammatory mediators

mast cell degranulation

the process by which mast cells rapidly and efficiently release inflammatory mediators, such as histamine, from internal granules into surrounding tissues

inflammatory response step two

the mediators, histamine, serotonin, cytokines, trigger several effects