A&P II Exam 3 - Lymphatic System, Respiratory System, Digestive System and Urinary System

Functions of Lymphatic System:

- Transports escaped fluids from the cardiovascular system back to the blood

- Plays essential roles in body defense and resistance to disease

- Transport dietary fats

Components of the lymphatic system:

- Lymph

- Lymphatic vessels

- Lymphatic trunks

- Lymphatic ducts

- Red bone marrow

- Thymus

- Spleen

- Lymph nodes

- Lymphatic tissues

Lymphatic system is diffuse, which means......

it is spread out across the body

Define lymph:

excess tissue fluid and plasma proteins

What do lymphatic vessels do?

transport excess lymph from tissues

What happens if fluids are not picked up?

fluid accumulates in tissues and edema occurs

Characteristics of lymph capillaries:

- Weave between tissue cells and blood capillaries

- Walls overlap to form flaplike minivalves

- Fluid leaks into lymph capillaries

- Capillaries are anchored to connective tissue by filaments

- Higher pressure on the inside closes mini valves

- Fluid is forced along the vessel

Characteristics of lymphatic vessels:

- Form a one-way system

- Lymph flows only toward the heart

- Thin-walled

- Larger vessels have valves

- Low-pressure, pumpless system

Lymph transport is aided by what?

- Milking action of skeletal muscles

- Pressure changes in thorax during breathing

- Smooth muscle in walls of lymphatics

Function of lymphatic collecting vessels:

- Collect lymph from lymph capillaries

- Return fluid to circulatory veins near the heart

What does the right lymphatic duct do?

drains the lymph from the right arm and the right side of the head and thorax

What does the thoracic duct do?

drains lymph from rest of body

What is the Formation and Flow of Lymph?

interstitial fluid -> lymph capillaries -> lymph vessels -> lymph trunks -> lymph ducts -> subclavian veins

What is the difference between ISF (interstitial fluid) and lymph?

ISF becomes lymph as soon as it enters the lymph capillaries

Lymphoid tissues and organs:

- Red bone marrow

- Thymus

- Spleen

- Lymph nodes

- Lymphatic tissues

- Tonsils

- Peyer's patches

- Appendix

What do lymph nodes do?

They filter lymph before it is returned to the blood

What do lymph nodes filter?

- Bacteria

- Viruses

- Cancer cells

- Foreign substances

What are the defense cells within the lymph nodes?

- macrophages

- lymphocytes

What do macrophages do?

engulf and destroy bacteria, viruses, and other foreign substances in lymph

What do lymphocytes do in the lymph node?

respond to foreign substances in lymph

What do afferent vessels do?

carry lymph to the lymph node to be filtered

What do efferent vessels do?

carry filtered lymph away from the lymph node

Lymph nodes are surrounded by a ______

capsule

The lymph node is divided into compartments by ________

trabeculae

Characteristics of Lymph Node Cortex:

- Contains follicles

- collections of lymphocytes

- Germinal centers enlarge when antibodies arereleased by plasma cells

Characteristics of Lymph Node Medulla:

- Contains phagocytic macrophages

Characteristics of spleen:

- Located on the left side of the abdomen

- Filters and cleans blood of bacteria, viruses, debris

- Provides a site for lymphocyte proliferation and immune surveillance

- Destroys worn-out red blood cells

- Stores platelets and acts as a blood reservoir

Characteristics of thymus:

- Found overlying the heart

- Functions at peak levels only during youth

Characteristics of tonsils:

- Small masses of lymphoid tissue deep to the mucosa surrounding the pharynx (throat)

- Trap and remove bacteria and other foreign pathogens entering the throat

- Tonsillitis results when the tonsils become congested with bacteria

Characteristics of peyer's patches:

- Found in the wall of the small intestine

- Similar lymphoid follicles are found in the appendix

- Macrophages capture and destroy bacteria in the intestine

What does Mucosa-associated lymphoid tissue (M A L T) do and include?

- Peyer's patches

- Tonsils

- Appendix

- Acts as a sentinel to protect respiratory and digestive tracts from foreign matter

What are the two mechanisms that make up the immune system that defends us from foreign materials?

- Innate (nonspecific) defense system

- Adaptive (specific) defense system

What does the Innate (nonspecific) defense system do?

- Responds immediately to protect body from all foreign materials

- Includes intact skin, mucous membranes,inflammatory response, various proteins

What provide the first line of defense against the invasion of microorganisms and what are its characteristics?

- Surface membrane barriers, such as the skin and mucous membranes

- Acidic skin secretions inhibit bacterial growth▪ Mucus traps microorganisms

- Gastric juices are acidic and kill pathogens

- Saliva and tears contain lysozyme (enzyme that destroys bacteria)

What provide a second line of defense and what are its characteristics?

- Cells and chemicals

- Natural killer cells and phagocytes

- Inflammatory response

- Chemicals that kill pathogens

- Fever

What are phagocytes?

- Cells such as neutrophils and macrophages engulf foreign material by phagocytosis

- The phagocytic vesicle is fused with a lysosome, and enzymes digest the cell's contents

Characteristics of Natural Killer (NK) cells:

- Roam the body in blood and lymph

- Lyse (burst) and kill cancer cells, virus-infected cells, and some other non-specific targets

- Release chemicals called perforin and granzymes to degrade target cell contents

- Release powerful inflammatory chemicals

What does the Inflammatory response do?

Triggered when body tissues are injured

What are the four most common indicators (cardinal signs)of acute inflammation?

- Redness

- Heat

- Pain

- Swelling (edema)

What are the functions of the inflammatory response?

- Prevents spread of damaging agents to nearby areas

- Disposes of cell debris and pathogens

- Sets the stage for repair

What is the process of the inflammatory response?

1. Neutrophils migrate to the area of inflammation by rolling along the vessel wall (following the scent of chemicals from inflammation)

2. Neutrophils squeeze through the capillary walls by diapedesis to sites of inflammation

3. Neutrophils gather in the precise site of tissue injury (positive chemotaxis) and consume any foreign material present

What is margination?

Neutrophils roll to the area of infection

What is diapedesis

squeezing through the capillary slits

What is chemotaxis

movement relative to chemicals

Antimicrobial proteins enhance innate defenses by:

- Attacking microorganisms directly

- Hindering reproduction of microorganisms

Most important types of antimicrobial proteins are.....

- Complement proteins

- Interferon

Antimicrobial proteins complement proteins characteristics:

- Complement refers to a group of at least 20 plasma proteins that circulate in the plasma

- Complement is activated when these plasma proteins encounter and attach to cells (known as complement fixation)

What is opsonization?

complement molecules attach to a bacteria which can act as a receptor for a macrophage

What are Membrane attack complexes (M A C s)?

- one result of complement fixation, produce holes or pores in cells

- Pores allow water to rush into the cell

- Cell bursts (lyses)

- Activated complement enhances the inflammatory response

What do interferons do?

- Small proteins secreted by virus-infected cells

- Bind to membrane receptors on healthy cell surfaces to interfere with the ability of viruses to multiply

- Do not help fight bacterial or fungal infections

What is interferon alpha (α)?

it is produced by cells infected with viruses. It attracts and stimulates NK cells and enhances resistance to viral infection

What does a fever do?

- mobilizes defenses

- accelerates repairs

- inhibits pathogens

Characteristics of fever:

- Abnormally high body temperature is a systemic response to invasion by microorganisms

- Hypothalamus regulates body temperature at 37°Celsius (98.6°F)

- The hypothalamus thermostat can be reset higher by pyrogens (secreted by white blood cells)

- High temperatures inhibit the release of iron and zinc (needed by bacteria) from the liver and spleen

- Fever also increases the speed of repair processes

What is the third line of defense (specific defense) and what does it do?

- Adaptive (specific) defense system

- Fights invaders that get past the innate system

- Specific defense is required for each type of invader

- The highly specific resistance to disease is immunity

- Antigens are targeted and destroyed by antibodies

What are the three aspects of adaptive defense?

- Antigen specific

- systemic

- memory

What is antigen specific in the adaptive body defense?

the adaptive defense system recognizes and acts against particular foreign substances

What is systemic in the adaptive body defense?

immunity that is not restricted to the initial infection site

What is memory in the adaptive body defense?

the adaptive defense system recognizes and mounts a stronger attack on previously encountered pathogens

What are the two arms of the adaptive defense system?

- Humoral immunity = antibody-mediated immunity

- Cellular immunity = cell mediated immunity

What is humoral immunity?

Provided by antibodies present in body fluids

What is cellular immunity?

Targets virus-infected cells, cancer cells, and cells of foreign grafts

What are antigens?

any substance capable of exciting the immune system and provoking an immune response

Characteristics of self-antigens

- Human cells have many protein and carbohydrate molecules which are recognized as self

- Self-antigens do not trigger an immune response in us but can be strongly antigenic to other people

- The presence of our cells in another person's body can trigger an immune response because they are foreign

- Restricts donors for transplants

What are haptens and what are their characteristics?

- they are incomplete antigens and are not antigenic by themselves

- When they link up with our own proteins, the immune system may recognize the combination as foreign and respond with an attack

- Found in poison ivy, animal dander, detergents, hair dyes, cosmetics

What do antigen-presenting cells (APC's) do?

help the lymphocytes but do not respond to specific antigens

Lymphocyte characteristics:

- Arise from hemocytoblasts of bone marrow

- Whether a lymphocyte matures into a B cell orT cell depends on where it becomes immunocompetent

What is immunocompetence?

The capability to respond to a specific antigen by binding to it with antigen-specific receptors that appear on the lymphocyte's surface

What do B-lymphocytes do?

produce antibodies and oversee humoral immunity

What do T-lymphocytes do?

constitute the cell-mediated arm of the adaptive defenses; do not make antibodies

WHat are Anti-Presenting cells (APCs)?

they engulf antigens and then present fragments of them on their own surfaces to be recognnized by T cells

What are the major types of cells behaving like APCs

- dendritic cells

- macrophages

- B lymphocytes

Define active immunity

occurs when B-cells encounter antigens and produce antibodies

Active immunity can be:

- naturally acquired during bacterial and viral infections

- artificially from vaccines

What is passive immunity?

occurs when antibodies are obtained from serum of an immune human or animal donor

Passive immunity can be:

- naturally acquired from a mother to her fetus or in the breast milk

- artificially acquired from immune serum or gamma globulin (donated antibodies like antivenom or antitoxin)

What are the two meanings of respiration?

- The exchange of oxygen and carbondioxide between the atmosphere andthe cells of an organism

- The utilization of oxygen in themitochondria of cells for theproduction of energy (ATP)

What are the respiratory structures in the upper respiratory system?

nose, pharynx, and associated structures

What are the respiratory structures in the lower respiratory system?

Larynx, trachea, bronchi and lungs

What are the two parts of the lower respiratory system?

- Conducting portion

- Respiratory portion

What are the conducting portions?

structures that warm, moisten and filter the incoming air

What are the respiratory portions?

structures that contain air sacs where gas exchange occurs

What is the respiratory pump and what are some examples of them?

- Structures involved in moving air in and out of the lungs

- Rib cage

- pleural membranes

- respiratory muscles

- elastic tissues of the lungs

What is gas exchange?

internal and external respiration

What is gas trasport?

- oxygen mostly combined with hemoglobin

- carbon dioxide mostly dissolved in plasma

What is cellular respiration?

use of oxygen by cells for the production of ATP

What are the respiratory systems functions?

- Provides oxygen and eliminates carbon dioxide

- Conditions air

- Regulates blood pH

- Voice production

- Olfaction

- Protection

What are the two chambers of the nasal cavities?

- vestibule

- nasal septum

What is the nasal vestibule?

- anterior portion just inside nares

- Contains nose hairs (Vibrissae) that remove coarse particles from incoming air

What is the nasal septum made of?

- articular cartilage (anterior)

- perpendicular plate of ethmoid

- vomer bone (posterior)

What are the internal nares (choanae)?

two openings that connect the nasal fossae to the nasopharynx

What are the chonchae (turbinates)?

- 3 scroll-like elevations on the lateral wall of each nasal cavity

- increases surface area

What are meatuses?

series of groove like passages formed by the conchae

What is the olfactory epithelium?

olfactory (smell) receptors lie in the membrane lining the superior nasal conchae and adjacent septum

What are the paranasal sinus structures?

- maxillary

- frontal

- sphenoid

- ethmoid

What are paranasal sinuses and what are their functions?

- Air filled spaces located in bones of skull

- Reduce the weight of the skull

- Serve as resonant chambers for voice production

Characteristics of Nasopharynx:

- continuous with the nasal cavity

- Posterior to and continuous with nasal cavity

- Superior to soft palate

- Contains pseudostratified columnar epithelium with goblet cells.

- Contains openings of Eustachian (auditory) tubes.

Characteristics of oropharynx:

- Middle portion of the pharynx

- Lies posterior to the oral cavity (mouth)

- Extends from the soft palate inferiorly to the level of the hyoid bone

- Palatine tonsils

- Lingual tonsils

- Lined with moist stratified squamous epithelium.

- Fauces

What is the fauces?

the opening from the mouth in to the oropharynx

Characteristics of laryngopharynx:

- Lowest portion of the pharynx

- Extends downward from the hyoid bone

- Becomes continuous with the esophagus and larynx

- Lined with moist stratified squamous epithelium

Characteristics of larynx:

- Short passageway that connects the pharynx with the trachea

- Houses the vocal cords

- Has a wall composed of 9 pieces of cartilage