Anatomy Test 4 Ch. 24

Lymphatic system function

prevents interstitial fluid from rising out of control and helps maintain blood volume

Lymphatic system function

lymphoid organs house lymphocytes, and assist in maturation or replication of the lymphocytes

Lymphatic system function

lymphocytes generate/initiate the immune response

Immune response

increases lymphocyte population when necessary

Edema

swelling of body tissues

Antigens

foreign or abnormal substances to the body (bacteria, viruses, cancer cells)

Antibodies

bind to antigens and alert cells of the immune system to come attack the antigen

MALT

Mucosa-Associated Lymphatic Tissue

Tonsils

large clusters of lymphoid cells and matrix

Tonsils

protect against ingested and inhaled pathogens

Pharyngeal tonsil

located in posterior wall of nasopharynx

Palatine tonsils

located in posterolateral oral cavity

Lingual tonsils

located posterior ⅓ of tongue

Thymus

bilobed organ, superior to heart

Thymus

infants and young children have a quite large ___, it degenerated with age and starts to regress around puberty (replaced with adipose tissue & non-functional)

Thymus

functions as a site for T-lymphocyte maturation and differentiation

Lymph nodes

small, round, encapsulated structures located along pathways of lymph vessels

Lymph nodes

functions to filter antigens in lymph and initiate immune response

Lymph nodes

widespread but often concentrated in clusters

Spleen

largest lymphoid organ, located in LUQ

Spleen

functions to filter antigens in blood and initiate immune response

Spleen

blood reservoir that releases formed elements when needed

Red bone marrow

found in spongy bone of axial skeleton and proximal epiphysis of each humerus and each femur

Red bone marrow

hemopoiesis occurs here

Hemopoiesis

blood cell production

T-lymphocytes

most abundant lymphocyte (70-85%), produced in red bone marrow, matures in thymus

T-lymphocytes

each ___ recognizes and destroys ONE SPECIFIC ANTIGEN (specificity)

B-lymphocytes

2nd most abundant lymphocyte (15-30%), produced and matures in red bone marrow

B-lymphocytes

produce antiBodies (immunoglobulins) that respond to antigens

B-lymphocytes

each ___ responds to ONE ANTIGEN (specificity)

Natural Killer (NK) cells

remaining small percent of lymphocytes, produced and matures in red bone marrow

Natural Killer (NK) cells

kill a wide variety of infected cells and some cancerous cells (NO SPECIFICITY)

Lymph

fluid transported within lymph vessels

Lymphatic capillaries

(smallest vessel) penetrate nearly every tissue to absorb interstitial fluid

Lymphatic capillaries

microscopic, close-ended vessels (ensure 1 directional flow) allows fluid to enter, but not leave

Lymphatic capillaries

composed of overlapping, thin endothelial cells

Lymphatic vessels

formed when lymphatic capillaries merge together, contains valves that prevent lymph from pooling and prevent backflow

Lymphatic vessels

contraction of nearby skeletal muscles assist in lymph movement

Lymphatic vessels

empty lymph nodes at regular intervals

Lymphatic Trunks

formed when lymphatic vessels merge together, removes lymph from major portion of body, and drains into one of two lymphatic ducts

Lymphatic Ducts

largest vessels that convey lymph back to venous circulation (2 of these)

Right lymphatic duct

(smallest) lymph from right side of the head and neck, right upper limb, right side of thorax, returns to RIGHT SUBCLAVIAN VEIN

Thoracic duct

(largest) drains lymph from left side of head and neck, left upper limb, left thorax, all of abdomen, right and left lower limbs, starts at DIAPHRAGM and returns lymph to LEFT SUBCLAVIAN VEIN

Inferior mesenteric vein, splenic vein, & superior mesenteric vein

3 mechanisms of venous return?

inferior mesenteric vein

drains blood from distal half of large intestine (descending and sigmoid colon) and rectum, drains into splenic vein

splenic vein

drains blood from spleen, stomach, pancreas

superior mesenteric vein

drains blood from small intestine and proximal half of large intestine (ascending & transverse colon)

hepatic portal vein

large vein that receives O2-poor, but nutrient rich blood from GI organs, formed when splenic and superior mesenteric veins converge

hepatic veins

drains liver capillaries once nutrient absorption occurs, drains into IVC

systolic blood pressure

first time you hear pulsation

diastolic blood pressure

when pulsations stop, blood is flowing evenly

pulse point

rhythmic throbbing of an arterial wall as blood is being pumped through it

hepatic portal system

most efficient route for handling absorbed substances

valves, skeletal muscle pump, respiratory pump

3 mechanisms to assist venous return?

skeletal muscle pump

contracting muscles squeeze veins, propel toward heart

respiratory pump

aids venous return from high to low pressure

inhale

diaphragm contracts and flattens

exhale

diaphragm relaxes and returns to original shape

• increase, decreases

• decrease, increases

during inhale:

• thoracic cavity volume ___ & thoracic pressure ___

• abdominal volume ___ & abdominal pressure ___

• decreases, increases

• increases, decreases

during exhale:

• thoracic cavity volume ___ & thoracic pressure ___

• abdominal volume ___ & abdominal pressure ___

blood pressure

force per unit area that blood everts against the inside wall of a vessel (mmHG)