remainder for exam 3

pages 2 and 3 of the study guide

functions of lymphatics

• transport fluids that escaped from the vascular system back to the blood

• house macrophages and lymphocytes which play an essential role in immunity

• filter pathogens, debris, abnormal cells

vessels - lymphatics

network that carries lymph fluid throughout the body

lymphatic capillaries

• blind ending in tissues

• very permeable

• have flap like mini valves

• allow entry of proteins, pathogens, and cells

collecting vessels

• formed by merging capillaries

• contain:

  • many valves

  • thin 3 layer walls

  • smooth muscle for contraction

right lymphatic duct drains…

right head, neck, thorax, right arm

thoracic duct drains…

the rest of the body

both the right lymphatic duct and the thoracic duct empty into

subclavian veins

what does lymph lack for movement

a central pump

5 ways lymph moves

1. smooth muscle contraction

2. skeletal muscle pump

3. respiratory pump

4. nearby artery pulsations

5. valves prevent backflow

lymphatic organs and functions

• lymph nodes - filter lymph and activate immune response

• spleen - filters blood, removes old RBCs

• thymus - T cell maturation (active before puberty)

• tonsils - protect against inhaled/swallowed pathogens

innate immunity - first line of defense

• skin

• mucus membranes

• saliva

• tears

• stomach acid

innate - second line of defense - inflammation

• triggered by injury or infection

• mast cells release histamine

what does the release of histamine by mast cells cause (3)

• increased permeability

• vasodilatation

• chemotaxis (attracts immune cells)

signs of inflammation

• redness

• heat

• swelling

• pain

keratinocytes

release signaling molecules, make up the epidermis

IL-1 alpha/TNF (tumor necrosis factor)

promotes inflammation

mast cells

release histamine

macrophages

release IL-8, phagocytosis

neutrophils

engulf bacteria

two important features of specific (adaptive) immunity

1. specificity (targets specific antigen)

2. memory (faster response upon re-exposure)

B cells

• plasma cells - secrete antibodies

• memory B cells

T cells - T lymphocytes

• helper T cells (CD4) - activate B cells to secrete antibodies

• cytotoxic T cells (CD8) - kill infected cells

MHC I

• on all nucleated cells

• present antigens to CD8 cells

MHC II

• on antigen-presenting cells (macrophages, B cells, dendritic cells)

• present to CD4 cells

antibodies

• Y shaped

• bind specific antigens

• produced by plasma cells

IgG

most abundant, secondary response, can cross the placenta barrier to the fetus

IgM

primary response

IgA

mucous membranes like saliva, tears, breastmilk

IgD

on the surface of B cells, serves as an antigen-binding receptor

IgE

least abundant, binds to basophils, eosinophils, mast cells; allergic reactions, parasites

primary response

IgM dominant

secondary response

IgG dominant, faster and stronger response than primary response

cell mediated immunity does not involve…

antibodies

cell mediated immunity is carried out by

cytotoxic cells (cytotoxic T cell - CD8)

why is cell mediated immunity important

bc after a virus or bacteria enters a cell, it can no longer be detected by the humoral immune response

cell mediated immunity targets

infected cells

cell mediated immunity works via

MHC I presentation

cell mediated immunity ____ ____ directly

kills cells directly

cardiac cycle

• one complete heartbeat (systole and diastole)

• about 65-75 bpm

systole

• ventricles contract → pressure rises

• AV valves close (prevents backflow)

• semilunar valves (aortic and pulmonary) open when ventricular pressure > arterial pressure

• blood is ejected from the left heart to the aorta and from the right heart to the pulmonary trunk

ESV

• end-systolic volume

• blood remaining after contraction

diastole

• ventricles relax → pressure drops

• AV valves (mitral and tricuspid) open and blood flows from atria to ventricles

• ventricles fill passively

• atrial contraction finishes filling

EDV

• end-diastolic volume

• volume in ventricles at the end of filling

S1 sound

• lub

• closure of the AV valves

• start of systole

S2 sound

• dub

• closure of semilunar valves

• start of diastole

cardiac output definition

blood pumped per minute

stroke volume

amount of blood ejected per beat

regulation of stroke volume - preload

• stretch of ventricular muscle before contraction

• directly related to EDV

• higher preload = higher force of contraction

• increased by

  • slow heart rate

  • increased venous return (exercise)

regulation of stroke volume - contractility

• strength of contraction independent of preload

• high contractility = low ESV, high SV

• influenced by sympathetic stimulation

regulation of stroke volume - afterload

• pressure ventricles must overcome to eject blood

• related to blood pressure

• high afterload (ex - hypertension) = low SV

ejection fraction

% of blood pumped out of the ventricle each beat (normal - 50-75%)

3 layers of arteries

1. tunica intima (inner)

2. tunica media (thick smooth muscle)

3. tunica adventitia (outer CT)

arteries

• thick walls, high pressure

• move blood away from the heart

elastic arteries

• closest to the heart (aorta, pulmonary trunk)

• stretch and recoil - maintain pressure

muscular arteries

thick smooth muscle - control distribution

arterioles

• smallest arteries

• major site of resistance and BP regulation

veins

• carry blood to heart

• thinner walls, low pressure

• hold about 70% of blood volume

• contains valves to prevent backflow

venous valves

• one way flaps

• prevent backflow (esp in legs)

• work with skeletal muscle pump

capillaries

• smallest vessels - site of exchange, connect veins and arteries

• only one cell thick

types of capillaries

• continuous - least permeable (muscle, brain)

• fenestrated - pores (kidneys)

• sinusoidal - very leaky (liver, spleen, bone marrow)

mean arterial pressure

average pressure in arteries

baroreceptors

• pressure sensors that detect stretch

• send signals to medulla to adjust BP

location of baroreceptors

• carotid sinus

  • monitors blood flow to the brain

  • signal via glossopharyngeal nerve

• aortic arch

  • monitors systematic BP

  • signal via vagus nerve

short term regulation of blood pressure

• nervous system

• adjusts

  • heart rate

  • contractility

  • vessel diameter

long term regulation of blood pressure

• RAAS system (renin angiotensin aldosterone system)

• triggered by low BP or low kidney perfusion

• increases blood volume and pressure

renin

a hormone released by the kidney that is released in response to:

• sympathetic stimulation

• reduced sodium chloride delivery to the distal convoluted tubule

• decreased blood flow to the kidney

1st renin facilitates the conversion of…

angiotensinogen → angiotensin I

angiotensin I

a weaker vasoconstrictor so it needs to be converted

angiotensin I is converted to _____ using…

angiotensin II using angiotensin converting enzyme (ACE)

angiotensin II

a potent vasoconstrictor

angiotensin II promotes

the release of aldosterone

aldosterone

holds onto sodium and warter

naive B cells express

antibodies (IgD) on their cell surface which serve as receptors for antigens

when a naive B cell encounters an antigen that matches it…

it divides into a memory B cell or a plasma cell

memory B cells

express the same membrane bound antibody as the original naive B cell

plasma cells

produce and secrete antigen specific antibodies for the remainder of its life cycle, antibody factories

what do B cells do to T cells

they activate, regulate, or suppress T cells by presenting antigen fragments on MHC-II molecules

what receptors do T cells have

• helper T cells: CD4 - interact with MHC class II molecules so helper T cells can recognize pathogen peptides that have been displayed by antigen presenting cells

• cytotoxic T cells: CD8

when a helper T cell recognizes a peptide on an antigen presenting cell..

they become activated

vasodilation - resistance, BP, TPR (afterload)

resistance, BP, TPR, and afterload dec

vasoconstriction - resistance, BP, TPR (afterload)

resistance, BP, TPR and afterload inc

EDV and SV relationship

the higher the EDV, the higher the SV

increased contraction elevates ____ and ____

cardiac output and blood pressure