Test 3 - Lymphatic/Respiratory

functions of lymphatic system

1. fluid balance

   1. immune defense

function of lymphatic - Fluid balance

returns excess interstitial fluid/proteins frim tissues to bloodstream

approx. 3 liters of fluid are collected/returned daily

function of lynphatuc - immune defense

contains lymphatic tissues, organs, and immune cells that detect and fight pathogens

what is lymph

fluid transported thru lymphatic vessels

contains fluid, proteins, cell debris, and immune cells

function of lymphatic vessels

1. collect excess fluid, proteins, debris, and cells from tissue

2. transport lymph toward the heart

3. filter lymph thru lymph nodes before it returns to bloodstream

   1. transport absorbed dietary fats from small intestine

how does lymph moce thru system

skeletal muscle contrctions

breathing-related pressure changes

valves

smooth muscle contractions in larger vessels

lymph pathway

lymphatic capillaries → lymphatic vessels → lymphatic trunks → lymphatic ducts → bloodstream

lymphatic capillaries

collect excess interstitial fluid from tissues

lymphatic vessels

carry lymph toward larger vessels and lymph nodes

lymphatic trunks

collect lymph from major regions of body

right lympatic duct

drains upper right quarter of body

empties into venous circulation near subclavian vein

thorasic duct

drains remaining ¾ of body and empties into venous circulation near left subclavian vein

cisterna chyli

enlarged lymph-collecting sac in adbomen at lower end of thorasic duct

collects lymph, including fat-rich lymph from digestive tract

lymph tissue is found everywhere except

CNS

corneas

bone

teeth

bone marrow

lymphatic capillaries vs blood capillaries

lymphatic

1. begin as blind-ended tubes in tissues

2. larger diameter and thinner walls

3. overlapping endothelial cells form once-way flips

4. allow proteins, debris, and some cells to enter

5. collect excess interstitial fluid

blood

1. connect arterioles to venues

2. generally smaller diameter

3. endothelial cells form blood vessel wall

4. less permeable to large substances

5. exchange substances between blood and tissue

   1. 
      

what happens to prevent collasping of capillaries and during inflammation

collagen anchoring fibers that prevent capillires from collapsing

during inflammation, their openings can become larger, allowing more fluid, proteins, and cells to enter

lacteals

specialized lymphatuic capilalries loacted in villi of small intestine

absorb dietary fats that are transported through lymphatuc system before reaching bloodstream

chyle

fat-rich lymph absorbed from small intestine that travels thru lymphatic vessels

compare structure of lympatic vessels to blood vessels

larger lymphatic vessels resemble veins and have 3 tunic layers

1. thinner walls

2. more internal valves to prevent backflow

3. more connections between vessels (anastomoses)

4. smooth muscle in larger vessels to help propel lymph

5. vasa vasorum, small blood vessels that supply walls of larger vessels

6. low pressure

   1. rely on muscle contractions, breathing, valves, and smooth muscle to move lymph

lymphatic cell types

T cells

B cells

T cells

lymphocytes

• mature in thymus

• participate in cell-mediated immunity

• attack foreign cells and virus

• help coordinate immune responses

• 80% lymphocytes

B cells

lymphocytes

• participate in antibody-mediated or humoral immunity

• when activated, become plasma cells

• plasma cells produce antibodies that bind to, immobilze, or mark antigens for destruction

• 10-15% of lymphocytes

macrophages

engulf pathogens, foreign substances, and cellular debris thru phagocytosis

monitor tissues for signs of infection

present antigens to lymphocytes to help actibate immune response

dentritic cells

present antigens to lymphocutes in lymph nodes

reticular cells and fibers

• cells produce retiruclar fibers

• fibers form supporting network called stroma

• framework supports lymphoid tissues and provides space for immune cells

diffuse lymphatic tissue

loosely organized lyphoid tissue found thrupughout the body, especially in digestuve tract

contains lymphocytes and macrophages assocoaited with reticular fibers

allows immune cells to monitor tissues for foreign antigens

lymph follicles

• dense colelctions of lymphocytes without surrounding capsule

• often contain germinal centers where activated B cells multiply

  • B cells can develop into plasma cells that produce antibodies

lymph nodes function

1. filter and cleanse lymph

2. trap foreign substances and pathogens

   1. activate immune response

lymph nodes structure

• surrounded by dense fibrous capsule

  • divided into cortex and medulla

  • cortex

  • medulla

  • afferent vessels

  • efferent vessels

lymph node cortex

contains lymphoid follicles with cells and germinal centers

lymph node medulla

contains B cells, T cells, and other immune cells

afferent vessels

carry lymph into lymph node

efferent vessels

cary lumph out of lymph node

locations of lymph nodes

concentrated in neck, armpits, groin, areas where limbs connect to trunk

these locations helo filter lymph before it returns to bloodstrea,

MALT

mucosa associated lymphoid tissue

• protects mucosal surfaces where pathogens may entee thru food/air

• includes tonsils, peyer’s patches, and lymphoid tissue in appendix

peyers patches

located in wall of the ileum of small intestine,

help detect and destroy bacteria before they enter deeper tissues

support long term immunity thru memory lymphocytes

tonsils

• located in pharynx

• help trap/remove pathogens entering thru nose and mouth

• contain crypts that can trap bacteria

  • repeated infections can lead to chronic tonsilitis

  • part os MALT

spleen

filters blood and helps detect pathopgens circulating in blood

• red pulp

• white pulp

  • soft organ and can bleed severely if injured

red pulp

removes old rbc and platelets

stores platlets and monocytes

white pulp

contains lymphocytes and support immune resposnce

thymus

• located in chest behind sternum

• most active during childhood

• produces thymosin to support T cell maturation

• helps ensure T cells recognize foreign antigens without attacking body

  • has blood-thymus barrier that protects developing T cells from exposure antigen

location/role

red bone marrow

inside certain bones

produces blood cells, B cell maturation

location/role

thymus

behind chest sternum

T cell maturation l

location/role

lymph nodes

along lymphatic vessels, neck, armpit, groin

filter lymph and activate immune responses

location/role

spleen

upper left abdomen

filters blood and removes old blood cells

location/role

tonsils

around the pharynx

trap pathogens entering thru food or air

location/role

peyers patches

illeum of smal intestine

protect against intestinal pathogens

location/role

appendix

attached to large intestine

contains lymphoid tissue involved in immune defense

location/role

diffuse lymphoid tissue

throughout tissues, especially in digestive tract

immune survalence

location/role

lymph follicles

within lymphoid tissues

B cell activiation and proliferation

primary lymphoid organs

red bone marrow

thymus

where lymphocytes develop and mature

secondary lymphoid organs/tissues

lymph nodes, spleen, tonsils, MALT, peyers patches, appendix

where immune response can be initiated

lymphedema

• swelling causes by blocked lymphatic drainage

• fluid accumulates in tissues bc it cannot return to bloodstream

  • cna occur after lymph nodes are removed

fix to lymphedema

compression garments can help limit fluid buildup

lymph-node transplant

cancer metastasis

• cancer cells enter lymphatic capillaries and travel to lymph nodes or other body sites

• in breast cancer, underarm lymphs may be checked for cancer cells

  • cancer in lymph nodes can indicate that the cancer has spread beyond its original site

bubonic plague

• bacterial disease transmitted by fleas that have fed on infected rodents

• cause severly swollen lymph nodes (buboes)

  • infection can spread to bloodstream and lungs

filariasis

parasitic disease transmitted by mosquitos

parasitic worms can obstruct lymphatic vessels

blocked lymph flow causes fluid buildup, severe swelling, and tissue damage

function of respiratory system

moves air in/out of lungs and provides large surface area for O2 and CO2 exchange

parts of the upper respiratory tract

nose

nasal cavity

paranasal sinuses

pharynx

function of nose and nasal canal

filter, warm and humiditfy incoming air

mucus traps particles

cillia help move trapped material toward pharynx

paranasal sinuses function

air filled sacs in skull that help warm, and humidify air

produce mucus

contribute to voice resonance

pharynx function

throat

passageway that conducts air from nasal cavity toward the larynx

includes nasopharynx, oropharynx, laryngopharynx

parts of the lower respiratory tract

larynx

trachea

bronchi

bronchioles

alveolar ducts/alveoli

lungs

larynx function

keeps airway open, directs air into trachea, contains vocal cords for sound production

epiglottis helps prevent food and liquid from entering airway during swallowing

trachea function

conducts air towards lungs

C-shaped cartilage rings help prevent it from collapsing

ciliated lining moves mucus and trapped debris upward

bronchi function

right and left primary bronchi enter lungs and branch into smaller bronchi

bronchioles function

smaller airways with smooth muscle that regulate airway diameter and resistance

alveolar ducts and alveoli function

smallest respiratory passages lead to alveoli

microscopic air sacs surrounded by pulomary capillaries

where most gas exchange occurs

lungs function

contain branching airway and alveoli

right lung has 3 lobes

left lung has 2 to accomodate the heart

conducting zone

extends from nose thru terminal bronchioles

• moves air toward and away from respiratory zone

• filters, warms, and humidifies air

• does NOT normally perform gas exchange

• includes nasal cavity, pharynx, larynx, trachea, bronchi, terminal bronchioles

respiratory zone

inclides respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli

• performs gas exchange between air and blood

• O2 diffuses from alveoli into pulmonary capillary blood

  • CO2 dissuses from blood into alveoli to be exhaled

respiratory mucosa

moist lining of airways

traps particles and cillia move mucus toward pharynx where is can be swallowed or expelled

pseudostratified ciliated columnar location and function

nasal cavity, trachea, bronchi

mucus traps particles, cillia move mucus

stratified squamos location and function

oropharynx, laryngopharynx, vocal folds

protects against abrasion

simple cuboidal location/function

bronchioles

secretion and airway protection

simple squamos location and function

alveoli

allows rapid gas exchange

mucociliary escalator

defense mechanism

cillia continuously move mucus and trapped particles up toward throat

smoking can damage collia and impair this clearing mechanism

cell types of alveolar sacs

1. type I

2. type II

3. alveolar macrophages

type I alveolar cells

very thin, simple squamos cells

cover most of alveolar surface

form much of the thin barrier across which O2 and CO2 diffuse

type II alveolar cells

cuboidal cells that secrete surfactant

surfactant lowers surface tension inside alveoli

helps prevent alveolar collapse and reduce the work needed to inflate the lungs

can divide and replace damaged alveolar cells

alveolar macrophages

immune cells that engulf dust, microorganisms, and debris

help protect the delicate gas-exchange surfaces from infection and foreign particles

respiratory membrane

thin barrier separating air inside an alveolus from blood inside pulmonary capillary

what does the respirtaotry capillary mainly consist of

1. thin fluid layer and surfactant lining the alveolus

2. alveolar type I cells

3. fused basement membrane and very thin interstitial region between alveolus and capillary

   1. capillary endothelial cell

function of respiratory membrane

O2 and CO2 diffuse across this barrier down their partial-pressure gradients

• O2 moves from alveolar air into the blood

• CO2 dioxide moves from the blood into alveoli

thin membrane and large surface area allows for rapid diffusion

2 blood supplies to lungs

bronchial circulation

pulmonary circulation

bronchial circulation

systemic blood supply that delivers oxygenated blood to nourish tissues of conducting airways and supporting lung structure

much of this blood returns thru systemic veins

pulmonary circulation

blood from R venticle travels thru pulmonary arteries to capillaries surrounding the alveoli

blood is relativly low in O2 and high in CO2

gas exchange occurs here

oxygenated blood retuns thru pulmonary veins to L atrium

key distinction between bronchial and pulmonary circulation

bronchial - nourishes lung tissue

pulmonary - performs gas exchange

ventilation perfusion coupling

pulmonary blood flow is adjusted according to alveolar O2 levels

low alveolar O2 causes nearby pulmonary arterioles to constrict, directing blood toward better ventilated regions

high alveolar O2 generally supports greater local blood flow

spirometry

measures volume of air inhaled/exhaled

TV

tidal volume

amount of air inhaled/exhaled during one normal quiet breath

500 nL

IRV

inspiratory reserve volume

additional air that can be forcibly after a normal inspiration

3000 mL

ERV

expiratory reserve volume

additional air that can be forcibly exhaled after a normal expiration

1,100 mL

RV

residual volume

air remaining in the lungs after the strongest possible expiration

helps prevent lung collapse

1,200 mL

IC

inspiratory capacity

TV + IRV

max amount inhaled after a normal expiration

FRC

functional residual capacity

ERV + RV

air remaining after normal expiration

VC

vital capacity

IRV + TV + ERV

max air exhaled after max inspiration

TLC

total lung capacity

VC + RV

total air in the lungs after max inspiration

FVC

forced vital capcity

total forcibly exhaled after taking deepest breathe possible

functions of respiratory system

1. gas exchange

2. pulmonary ventilation

3. air condotioning and protection

4. sound production

5. olfaction

6. blood pressure regulation

7. acid-base regulation