Exam 2 Flashcards
What are the deviations from normal mean arterial pressure?
Less than normal:
Systolic/Diastolic 90/60 or less = hypotension: inadequate blood flow to tissues
More than normal:
140/90+ = hypertension: stresses cardiovascular system (chambers and vessels) increasing the risk of aneurism and breaking blood vessels
What is Mean Arterial Pressure (MAP) proportional to?
Cardiac output (CO) and Total peripheral resistance (TPR)
CO: amount of blood pumped from a ventricle in a minute (SV x HR)
TPR: resistance to flow in arterioles.
How does cardiac output affect mean arterial pressure?
Increasing the cardiac output increases the amount of volume into the arteries this increases the MAP because blood fills the artery faster than it can get out,
Why is total peripheral resistance variable and how does it affect mean arterial pressure?
Variable because arterioles have a lot of smooth muscle for vasoconstriction/dialation
Increased TPR means that the arterioles are constricted decreasing the space in them blood backs up into the arteries increasing MAP
How does the nervous system respond to high blood pressure? What is this called?
Baroreceptor reflex:
1) high blood pressure
2) arteries stretched more than normal
3) baroreceptors, stretch receptors in the carotid artery and aorta, are activated
4) sensory neurons are stimulated
5) stimulates cardiovascular control center of the medulla (cardioinhibitory)
6) excite parasympathetic neurons in CN X, vagus nerve
7) Stimulate the heart through the SA & AV nodes hyperpolarizing them with ACh
8) decreases heart rate because the cells do not signal as fast
9) decreases cardiac output decreasing the blood pressure
How does the nervous system respond to low blood pressure? What is this called?
Baroreceptor reflex:
1) low blood pressure
2) arteries stretched low than normal
3) baroreceptors, stretch receptors in the carotid artery and aorta, are activated
4) sensory neurons are stimulated
5) stimulates cardiovascular control center of the medulla (cardioexcitatory)
6) excite sympathetic neurons in spinal cord –> sympathetic chain ganglia
7) Stimulate the SA, AV, ventricles, arterioles and veins
8) SA AV increases heart rate b/c cells signal faster
ventricles: increase stroke volume
arterioles & veins: vasoconstrict
9) increased Cardiac output, increased total peripheral resistance, increased venous return (increasing stroke volume, increasing CO) increasing blood pressure
What are the three aspects of the lymphatic system?
Lymphatic vessels: run parallel to veins and arteries
Lymphoid tissue & organs: stroma- abundant reticular CT in lymphatic tissue & organs, involved in removing damaged cells and debris, get nutrients, immune response
Lymph: fluid CT, comes from interstitial fluid (between cells) when it enters L. vessel called lymph
What are the functions of the lymphatic system?
1) bring fluid back into circulation from interstitial spaces preventing edema (from fluid build up b/c cancerous cell blockages, parasitic infections “elephantiasis”
2) Absorb digested fat: in intestinal mucosa lymph capillaries called lacteals b/c have milky appearance because contain lots of fat
3) Cleanse lymph and fight infection
-macrophages and lymphocytes
Where are lymphatic capillaries found?
In the same areas we find cardiovascular capillaries. In almost all cells in the body except the skeletal system.
What makes lymphatic capillaries so different than other capillaries and what do they absorb?
Lymph capillaries are much more permeable due to endothelial flaps (flaps in between cells) allowing large molecules to pass through
Absorb: cells pathogens (things that cause infection), cancer cells, proteins, chylomicrons (fat-containing particles)
Why lymph nodes are checked for cancer. Cancer cells get into lymphatic vessels and collect in the nodes
How are lymphatic vessels similar and different to cardiovascular vessels?
They both have the same three tunics and similar composition of the tunics. Both large versions of these vessels get nutrients from vasa vasorum.
Lymphatic vessels have thinner walls with more internal valves because nothing is giving it pressure to flow. They are also more interconnected.
Where are lymphatic vessels found?
Collecting vessels in the skin travel with superficial veins.
Deep vessels travel with the arteries
What is special about the right and left lymphatic vessels?
They are not symmetrical.
Right lymphatic duct drains right thoracic, arm, and head regions into the right subclavian vein.
Thoracic duct drains the left head, arm, and thoracic regions as well as the legs, abdominal and pelvic regions into the left subclavian vein.
this is how interstitial fluid is brought back into circulation
How is lymph moved?
There is no pump so lymph uses:
1) muscular pump and pulsations of nearby arteries
2) Respiratory pump
3) Contractions of smooth muscle in the walls of lymphatic vessels.
What are the lymphoid cells?
Macrophages: engulf worn-out cells, cell debris, sometimes while wandering encounters something, phagocatizes it then warns the T-cell that something is up
Lymphocytes: involved in immune response, protects body against cells expressing non-native antigens (other organisms have antigens)
T cells, Natural Killer cells, b cells, plasma cells
What do T cells do?
Start immune response, activated by weird cells (these are the cells destroyed by HIV).
immune response cannot start without T cells
What do Natural Killer cells do?
innate immune system: wander and kill what does not have MHC I antigen
-all body cells with nuclei have MHC I
-cancer cells, foreign cells, & cells with a viral infection do not have MHC I
What do B cells do?
Start the antibody production by producing plasma cells that pump out tons of antibodies
What are the primary and secondary lymphoid organs?
Primary:
bone marrow
thymus: lymphocyte maturation
Secondary:
lymph nodes, spleen, MALT, and GALT
What does the bone marrow do for the lymphatic system?
It produces blood cells including lymphocytes, particularly B-cells & T-cells
What role does the thymus play in the lymphatic system?
Most active in the neonatal to pre-adolescent period the thymus allows the T cells to mature and become immunocompetent (able to recognize non-self antigens) and self tolerant (does not attack normal body antigens)
Thymus slowly atrophies after puberty and is replaced with fat
What are the lymph nodes?
Lymph nodes are hundreds of balls of lymphoid cells and proteins that cluster along a lymph vessel each with a size of a few millimeters to 1-2 cm. They can be felt where they are highly concentrated (armpit, groin, neck)
What role do lymph nodes play in the lymphatic system?
Lymph nodes use macrophages to filter out and destroy microorganisms and debris in the lymph.
They also activate the immune system by monitoring for antigens and notifying T-cells to mount an attack against them.
What is the spleen and what is its structure?
It is the largest lymphoid organ. In the spleen the strong fibrous capsule is missing (unlike other lymphoid organs). It has lymphocytes and macrophages and has two areas: white pulp and red pulp
What role does the spleen play in the lymphatic system?
- Lymphocytes: this is where some B cells hand out for the immune system
- Blood cleansing: macrophages remove old erythrocytes, platelets, and debris in the blood
- Erythrocyte and Hb breakdown and iron storage
- Platelet and RBC storage
- Fetal erythrocyte production
What is MALT and what is its role in the lymphatic system?
Mucosa-associated lymphatic tissue
Functions to protect the digestive and respiratory systems
Examples: tonsils, Peyer’s patches, the appendix, and lymphoid nodules in the walls of the bronchi
What are the tonsils and what are their role in the lymphatic system?
Tubal (medial top), adenoid (center top), palantine (lateral), lingual (under tongue)
Functions to form a ring of lymphoid tissue around the pharynx to trap pathogens from the air and food
What is GALT and what is its role in the immune system?
gastrointestinal-associated lymphatic tissue
Peyer’s patches and appendix function to destroy bacteria, preventing them from breaching the intestinal wall
What are Peyer’s patches?
Peyer’s patches: isolated clusters of lymphoid tissue similar to tonsils found in the wall of the distal portion of the small intestine (ileum) similar to structures found in appendix
What is the function of the immune system and what are the two divisions?
Functions to distinguish between self and non-self and then destroyed non-self.
Innate immune response and adaptive/acquired immune response
these divisions are intertwined and are not completely separate responses
What are the general aspects of the innate immune response?
Non-specific (general), fast, short terms, present from birth, centers around inflammation, uses the same strategies no matter what it is fighting
What are the general aspects of the acquired immune response?
Specific, slow (but powerful, this is how you get over something), long-term: it keeps a memory of pathogens (so it is built over time)
What are the surface barriers of the immune system?
Physical and chemical barriers of the cutaneous and mucous membranes provide a barrier to most microorganisms
What are the chemical barriers of cutaneous and mucous membranes?
Acid: acidity of skin, stomach acid, urinary tract & vagina inhibits the growth of microorganisms
Enzymes: in saliva, respiratory mucus, and lacrimal fluid (tears) kill some microorganisms
Mucin: Sticky mucus that lines digestive and respiratory tract traps microorganism
What are the physical barriers of cutaneous and mucous membranes?
Stratified squamous epithelium produces physical barrier to abrasion and infection
Nose-hairs trap inhaled particles
Cilia of respiratory tract sweeps mucus containing microorganisms away from lungs
When is the innate immune system needed and what does it use?
Necessary if microorganisms invade deeper tissue: uses inflammatory response, fever, phagocytes, natural killer (NK) cells, and antimicrobial proteins (interferons and complete proteins)
What causes inflammation?
Chemical messengers called inflammatory cytokines–a term that can include local and distant control, but it associated with the immune system. Cytokines are released by any time of cell for different purposes. Released by tissue damage and as a response to pathogens
(cause vasodilation of local arterioles, make capillaries leaky, and attract phagocytes)
What is the purpose of inflammation?
To create a barrier to prevent the spread of a pathogen/ damaging agent, to bring in WBCs, disposes of cell debris and pathogens, alerts adaptive immune system, and sets the stage for repair
What are the signs of inflammation and what causes these signs?
Redness, heat, swelling, and pain
Cytokines cause vasodilation to bring in WBC and provide a barrier (redness & heat)
& cause leaky capillaries by increasing the spaces between endothelial cells to allow fluid, blood cells and proteins to leak out. WBC after diapedesis follow chemotoxins to site (chemotaxis). The leakage of antibodies and cytokines lead to a decrease in osmotic pressure causing swelling and then pain
What is a fever?
An abnormally high body temperature. a systemic (whole body) response to invading microorganisms