Cardiovascular system pt 2

3 layers in arteries and veins

• tunica externa or adventitia

• tunica media

• tunica intima

tunica externa or adventitia

• loose CT

• thickness varies with vessel size

tunica media

• smooth muscle

  • does not pump blood

  • constricts or dilates vessels

• CT

  • elastic in arteries

  • loose in veins

• thicker in arteries

why thicker in arteries?

• more tunica, elastic tissue, than veins

• arteries are pressure reservoirs, allows for expansion

  • elastic recoil

• veins have smaller tunica media, are volume reservoirs

  • expandable

tunica intima

• deepest

• simple squamous 

• only layer in capillaries

  • one cell layer

  • leaky

  • diffusion

arteries include

• TE

• TM

• TI

• blood flows away from the heart

• oxygenated

veins include

• TE

• TM

• TI

• also have endothelium

• return flow

• deoxygenated blood

acceptions to veins and arteries

• pulmonary artery

  • RV to lung

• pulmonary vein

  • lungs to LA

• fetal arteries and vein

  • umbilical arteries, veins

venule includes

TE

endothelium

arteriole include

• smooth muscle

• endothelium

capillaries include

• pores

• endothelium (tunica intima)

  • leaky

• basement membrane 

capillaries

• found all over body

• entered by arterioles

• exited by venules

• precapillary sphincter

  • smooth muscle around arteriole

  • shunts blood to areas that need oxygen

capillary dynamics

• pressure in is greater than pressure out

• hydrostatic pressure

• oncotic pressure

• plasma and substances dissolved in it

• starling forces

• osmotic pressure

• lymph vessels

hydrostatic pressure

• generated by pressure of fluid inside and outside the capillary

oncotic pressure

• pressure of proteins in interstitial space

plasma and substances dissolved in it

• tend to leave blood from capillaries into tissues

starling forces

• fluid movement is due to filtration across the wall of a capillary is dependent on the balance between the hydrostatic pressure gradient and the oncotic pressure gradient across the capillary

• force out O2, amino acids, hormones, water, also recover fluid

• water follows high solute levels

  • driven in at venule end

  • CO2 as well

• blood cells and proteins do not leave

osmotic pressure

• important so not all plasma leaves

lymph vessels

• recover lost fluids and lost plasma

blood flows from high pressure to low pressure

• aorta to veniles

pressure maintained by elasticity to arterial walls, which allows for

• keeps blood moving forward

• measure BP in peripheral arteries

• pressure does drop as arterial size decreases

• further pressure drop in capillaries

• pressure very low in veins

how does blood get back to the heart

• in veins

  • no elasticity and drop in pressure

• skeletal muscle contraction to move body

• smooth muscle contraction of internal organs

• valves

  • prevent backflow

• respiration

  • vacuum in thoracic cavity sucks blood toward heart during inhalation

lymphatic system

• part of circulatory system

• thin walled vessels

• same 3 layers as veins

• recovers fluid, proteins

  • capillaries to interstitial fluid

  • lymph

  • most lymph is clear and colorless

lymph vessels parallel veins function

• drain lymph from body tissue and from lymph node to lymph node

LS: returns to circulation

• meets cranial vena cava

  • thoracic duct

• same mechanism as blood in veins

  • respiration, valves, skeletal M contraction

LS: lacteals

• lymph vessels from intestine

  • contain chyle

  • milky white

    • absorbed fats

LS: nodules and nodes

• collection of lymphocytes

• lymph nodes

  • groups of nodules in specific places

• lymph filters through

• palpable

  • submandibular

  • prescapular

  • ancillary

  • inguinal

  • popliteal

spleen

• largest lymphatic organ

• immunity from lymphatic nodules

• RBC storage

• filters and removes dead or dying cells

• part of mononuclear phagocyte system

• stores iron

blood

• 7-10% of body weight

• function

  • transport gases, nutrients, hormones, heat throughout body

• pH 7.35-7.45

blood composition

• plasma/serum

  • 55-70% blood volume

  • liquid portion

  • components

    • water 92

    • electrolytes 

    • vitalims

    • limits

    • proteins 7

      • albumin 55

      • globulins 38

      • fibrogen 7

plasma

• from blood

• anticoagulant added

• calls are at bottom, clear liquid at top

serum

• clear liquid from clotted blood

• slightly less total protein than plasma

formed elements

• cells

• erythrocytes

• leukocytes

• agranulocytes

• thrombocytes

erythrocytes

• RBCs

• contain hemoglobin to carry oxygen

  • tetramer

  • globin

  • heme

    • iron

• round, biconcave i most mallams

  • camelids have oval

• non nucleated in mammals

  • nuclei present in birds, reptiles, amphibians

• most common blood cells

leukocytes

• WBCs

• granulocytes

  • neutrophils

  • eosinophils

  • basophil

neutrophils

• granules dont stain

• segmented nuclei

• phagocytic

• associated with acute infections, bacterial

• 60% of total WBC

eosinophils

• reddish or pink

• bilobed nuclei

• associated with parasitic infections, allergic reactions

• 3%

basophil

• blue or purple granules

• nucleus not easily seen

• allergic reactions, parasitic infections

• mast cells

• rare in peripheral blood

  • 1%

agranulocytes

• don't have specific granules

• monocytes

• lymphocytes

monocytes

• largest WBC

• indented nucleus

• phagocytic, macrophages in other tissues

• 5% of total WBC count

lymphocytes

• small, medium, and large

• nucleus large and round

• cytoplasm stain blue, nucleus purple

• 2nd most numerous WBC in mammals

• b cells

• t cells

b cells

• produce antibodies of humoral immunity

• mature in bone marrow

t cells

• in thymus

  • organ cranial to heart in young animals

• cytotoxic

  • bind foreign cells to kill them

• suppressor

  • suppress autoimmune response

• helper

  • assist killer

thrombocytes

• platelets

• fragments of large cells

  • megakaryocytes

    • found in bone marrow

• function as part of hemostasis

  • stop bleeding

blood cell formation

• hematopoiesis

  • occurs in bone marrow

  • erythropoiesis

  • leukopoiesis

erythropoiesis

• erythropoietin

  • hormone from kidney

  • stimulates new RBC when decreases O in blood

• young RBC may have nuclei or be reticulocytes

leukopoiesis

• stem cell progenitor

• WBC

RBC destruction

• mononuclear phagocytic system MPS

• macrophages in kidney, liver, spleen, and lymph nodes recognize old RBCs and take them out of circulation

• HB may be partially recycles

  • especially iron

• leftovers become bilirubin

  • yellow

  • excreted in urine and feces

  • blockage of bile ducts

    • overload causes jaundice

leukocytes

• philia and cytosis

• penia

philia and cytosis

• increased numbers of cells

penia

• decreased numbers of cells

RBC

• polycythemia

• anemia

polycythemia

increases numbers of cells

anemia

decreased numbers of cells