Sridah/ Bio Med Semester 2 Term 1 Flashcards

Question

Heart valves : AV valves:

Answer 1

Heart valves ensure unidirectional blood flow through the heart ▪ Atrioventricular (AV) valves lie between the atria and the ventricles ▪ AV valves prevent backflow into the atria when ventricles contract Chordae tendineae anchor AV valves to papillary muscles

Answer 2

First sound occurs as AV valves close and signifies beginning of systole ▪ Second sound occurs when SL valves close at the beginning of ventricular diastole

Answer 3

▪ Systole – contraction of heart muscle ▪ Diastole – relaxation of heart muscle

Answer 4

▪ The hormones epinephrine and thyroxine increase heart rate ▪ Intra- and extracellular ion concentrations must be maintained for normal heart function

Answer 5

Sympathetic nervous system (SNS) stimulation is activated by stress, anxiety, excitement, or exercise ▪ Parasympathetic nervous system (PNS) stimulation is mediated by acetylcholine and opposes the SNS ▪ PNS dominates the autonomic stimulation, slowing heart rate and causing vagal tone

Answer 6

Interleukins Colony Stimulating Factors these both promote and stimulate division of WBC

Answer 7

Myeloblast ▪ Monoblast

Answer 8

Lymphoblasts

Answer 9

1.Vasucular spasms due to injury 2.Platlet plug 3. Coagulation : blood thickening

Answer 10

Epithelial membranes produce protective chemicals that destroy microorganisms ▪ Skin acidity (pH of 3 to 5) inhibits bacterial growth ▪ Sebum (oil) contains chemicals toxic to bacteria ▪ Stomach mucosae secrete concentrated HCl and protein-digesting enzymes ▪ Saliva and lacrimal fluid contain lysozyme which destroys bacteria ▪ Mucus traps microorganisms that enter the digestive and respiratory systems

Answer 11

Skin, mucous membranes, and their secretions make up the first line of defense ▪ Keratin in the skin: ▪ Presents a formidable physical barrier to most microorganisms ▪ Is resistant to weak acids and bases, bacterial enzymes, and toxins ▪ Mucosae provide similar mechanical barriers

Answer 12

Mucus-coated hairs in the nose trap inhaled particles ▪ Mucosa of the upper respiratory tract is ciliated ▪ Cilia sweep dust- and bacteria-laden mucus away from lower respiratory passages

Answer 13

The body uses nonspecific cellular and chemical devices to protect itself ▪ Phagocytes and natural killer (NK) cells ▪ Antimicrobial proteins in blood and tissue fluid ▪ Inflammatory response enlists macrophages, mast cells, WBCs, and chemicals

Answer 14

▪ Microbes adhere to the phagocyte ▪ Pseudopods engulf the particle (antigen) into a phagosome ▪ Phagosomes fuse with a lysosome to form a phagolysosome ▪ Invaders in the phagolysosome are digested by proteolytic enzymes ▪ Indigestible and residual material is removed by exocytosis

Answer 15

Cells that can kill cancer cells and virus-infected cells ▪ Natural killer cells: ▪ Are a small, distinct group of large granular leukocytes (WBC’s) ▪ React nonspecifically and eliminate cancerous and virus-infected cells ▪ Kill their target cells by releasing perforins and other cytolytic chemicals that attack the target cells membrane ▪ Secrete potent chemicals that enhance the inflammatory response

Answer 16

▪ The inflammatory response is triggered whenever body tissues are injured ▪ Prevents the spread of damaging agents to nearby tissues ▪ Disposes of cell debris and pathogens ▪ Sets the stage for repair processes ▪ The four cardinal signs of acute inflammation are redness, heat, swelling, and pain

Answer 17

▪ Begins with a flood of inflammatory chemicals released into the extracellular fluid ▪ Inflammatory mediators: ▪ Include kinins, prostaglandins (PGs), complement, and cytokines ▪ Are released by injured tissue, phagocytes, lymphocytes, and mast cells ▪ Cause local small blood vessels to dilate, resulting in hyperemia

Answer 18

▪ Chemicals liberated by the inflammatory response increase the permeability of local capillaries ▪ Exudate (fluid containing proteins, clotting factors, and antibodies): ▪ Seeps into tissue spaces causing local edema (swelling), which contributes to the sensation of pain

Answer 19

The surge of protein-rich fluids into tissue spaces (edema): ▪ Helps to dilute harmful substances ▪ Brings in large quantities of oxygen and nutrients needed for repair ▪ Allows entry of clotting proteins, which prevents the spread of bacteria

Answer 20

▪ Leukocytosis – neutrophils are released from the bone marrow in response to leukocytosis-inducing factors released by injured cells ▪ Margination – neutrophils cling to the walls of capillaries in the injured area ▪ Diapedesis – neutrophils squeeze through capillary walls and begin phagocytosis ▪ Chemotaxis – inflammatory chemicals attract neutrophils to the injury site

Answer 21

Abnormally high body temperature in response to invading microorganisms ▪ The body’s thermostat is reset upwards in response to pyrogens, chemicals secreted by leukocytes and macrophages exposed to bacteria and other foreign substances

Answer 22

Immature lymphocytes released from bone marrow are essentially identical ▪ Whether a lymphocyte matures into a B cell or a T cell depends on where in the body it becomes immunocompetent ▪ B cells mature in the bone marrow ▪ T cells mature in the thymus

Answer 23

The liver and spleen to sequester iron and zinc (needed by microorganisms) ▪ An increase in the metabolic rate, which speeds up tissue repair

Answer 24

genes that synthesis IFN are activated with a host cell is invaded by a virus Interferons leave the infected call and enter neighboring cells Interferon activates PKR- which blocks viral reproduction in the neighboring cell

Answer 25

Interferon : hindering microorganisms abilty to reproduce Complement protiens - attacking microorganisims directly

Answer 26

Our cells are dotted with protein molecules (self-antigens) that are not antigenic to us but are strongly antigenic to others ▪ One type of these, MHC proteins, mark a cell as self ▪ The two classes of MHC proteins are: ▪ Class I MHC proteins – found on virtually all body cells ▪ Class II MHC proteins – found on certain cells in the immune response

Answer 27

▪ The adaptive immune system is antigen-specific, systemic, and has memory ▪ It has two separate but overlapping arms ▪ Humoral, or antibody-mediated immunity ▪ Cellular, or cell-mediated immunity

Answer 28

▪ Major rolls in immunity are: ▪ To engulf foreign particles ▪ To present fragments of antigens on their own surfaces, to be recognized by T cells ▪ Major APCs are dendritic cells (DCs), macrophages, and activated B cells ▪ The major initiators of adaptive immunity are DCs, which actively migrate to the lymph nodes and secondary lymphoid organs and present antigens to T and B cells

Answer 29

Soluble antibodies ▪ The simplest ammunition of the immune response ▪ Interact in extracellular environments such as body secretions, tissue fluid, blood, and lymph

Answer 30

T cells recognize and respond only to processed fragments of antigen displayed on the surface of body cells ▪ T cells are best suited for cell-to-cell interactions, and target: ▪ Cells infected with viruses, bacteria, or intracellular parasites ▪ Abnormal or cancerous cells ▪ Cells of infused or transplanted foreign tissue

Answer 31

Nonself (the antigen) ▪ Self (a MHC protein of a body cell)

Sridah/ Bio Med Semester 2 Term 1 Flashcards

(56 cards)