ANSC 2306 Exam 3

Blood

Composed of cells (formed elements) and fluid (plasma)

Plasma

Liquid portion of blood containing water

Erythrocytes

Red blood cells that transport oxygen and some carbon dioxide

Leukocytes

White blood cells involved in immune defense

Thrombocytes

Platelets that function in blood clotting

Hemoglobin

Protein in red blood cells that carries oxygen and gives blood its red color

Hemoglobin color change

Bright red when bound to oxygen and darker/purplish when carrying more carbon dioxide

Bilirubin

Yellow pigment from hemoglobin breakdown that contributes to plasma color

Blood percentage of body weight

Approximately 8-10 percent of total body weight

Plasma proteins

Include albumins

Albumins

Maintain osmotic pressure and help keep fluid in the bloodstream

Hematocrit

Percentage of blood volume made up of red blood cells

Hematocrit determination

Measured by centrifuging blood to separate layers

Hematocrit layers

Plasma on top

Buffy coat

Thin layer containing leukocytes and platelets

Packed cell volume

Bottom layer made of red blood cells

Low hematocrit

Indicates possible anemia

High hematocrit

Indicates possible dehydration or polycythemia

RBC shape

Biconcave disc shape that increases surface area for gas exchange

RBC flexibility

Allows red blood cells to pass through narrow capillaries

RBC hypotonic solution

Cells swell and may rupture due to water influx (hemolysis)

RBC production stimulus

Triggered by low oxygen levels in the body

Hemoglobin structure

Contains four heme groups with iron and globin protein chains

Hemoglobin and CO2

Can bind carbon dioxide but this reduces oxygen transport efficiency

RBC lifespan

Approximately 120 days

RBC production site

Bone marrow

RBC destruction

Occurs in liver and spleen

Iron recycling

Iron from hemoglobin is reused by the body

Bilirubin formation

Produced from hemoglobin breakdown as waste

Platelets

Cell fragments that initiate clot formation

Platelet activation

Platelets develop pseudopods and stick together to form a plug

Platelet plug

Initial temporary clot at site of injury

Clotting factors

Proteins in plasma that form fibrin to stabilize clots

Fibrinogen

Soluble plasma protein converted into fibrin during clotting

Fibrin

Protein that forms a mesh to strengthen blood clots

Clot formation sequence

Platelet plug forms first then fibrin mesh stabilizes it

Blood functions

Transport nutrients hormones and wastes regulate pH temperature immune defense and clotting

Specific immunity

Adaptive immune response that targets specific pathogens and develops memory

Nonspecific immunity

Innate immune response that acts quickly against general threats

First line of defense

Nonspecific defenses such as skin mucus and barriers

Macrophages

Nonspecific immune cells that engulf pathogens through phagocytosis

Neutrophils

First responder immune cells that perform phagocytosis

Natural killer cells

Nonspecific cells that kill infected or abnormal cells without prior exposure

B cells

Specific immune cells that produce antibodies

T helper cells

Coordinate immune response and activate other immune cells

T killer cells

Destroy infected cells after recognizing specific antigens

Antibodies

Proteins made by B cells that bind to antigens

Antibody function

Neutralize pathogens tag them for destruction and activate immune responses

Antigen

Foreign substance that triggers an immune response

Direct attack immune cells

T killer cells and natural killer cells destroy infected cells

Flagging pathogens

Antibodies and macrophages mark pathogens for destruction

Opsonization

Process of tagging pathogens to enhance phagocytosis

Passive immunity

Immunity gained from another source such as antibodies in colostrum

Permeabilize

To make a cell membrane leaky leading to cell death

Phagocytosis

Process where a cell engulfs and digests harmful particles

Phagocytosis steps

Engulfment formation of phagosome fusion with lysosome digestion

Lysosomes

Organelles containing enzymes that break down pathogens

Immune memory

Created by memory B and T cells for faster future responses

Vaccination principle

Exposes body to antigen to build immune memory without causing disease

NK cells vs T killer cells

NK cells act nonspecifically while T killer cells require antigen recognition

Mechanical digestion

Physical breakdown of food into smaller pieces without changing chemical structure

Acidic digestion

Breakdown of food by hydrochloric acid in the stomach which denatures proteins and kills microbes

Enzymatic digestion

Chemical breakdown of food using enzymes into absorbable molecules

Digestion

Process of breaking down food into smaller molecules

Absorption

Movement of digested molecules into the bloodstream or lymph

Ruminant animals

Animals with a four compartment stomach that allows microbial digestion of fibrous plant material

Ruminant stomach compartments

Rumen reticulum omasum and abomasum

Monogastric animals

Animals with a single chamber stomach such as humans and horses

Horse digestion

Monogastric but has a large cecum that allows limited microbial fermentation

Saliva

Secretion that lubricates food and aids in mastication and swallowing

Mastication

Chewing of food

Deglutition

Swallowing of food

Saliva contribution to stomach water

Approximately 80 percent of stomach water comes from saliva

Salivary amylase

Enzyme that begins carbohydrate digestion in the mouth

Autonomic control of digestion

Both parasympathetic and sympathetic systems regulate digestive activity

Parasympathetic digestion effect

Stimulates digestion and enzyme secretion

Sympathetic digestion effect

Inhibits digestion and reduces enzyme secretion

Pepsinogen

Inactive enzyme secreted by chief cells in the stomach

Pepsin

Active enzyme that digests proteins formed when pepsinogen is activated by HCl

Parietal cells

Stomach cells that secrete hydrochloric acid

Fundic region

Upper part of the stomach where parietal and chief cells are located

Hydrochloric acid function

Activates pepsinogen and creates an acidic environment for digestion

Pancreas exocrine function

Secretes digestive enzymes into the small intestine lumen not into the bloodstream

Proteases

Enzymes that break down proteins into amino acids

Lipase

Enzyme that breaks down fats into fatty acids and glycerol

Amylase

Enzyme that breaks down carbohydrates into simple sugars

Gastrin

Hormone that stimulates secretion of gastric acid and digestive enzymes

Secretin

Hormone that stimulates pancreas to release bicarbonate to neutralize stomach acid in small intestine

Cholecystokinin CCK

Hormone that stimulates gallbladder contraction and pancreatic enzyme release

Bile

Substance produced by the liver that helps emulsify fats

Bile pigments

Include bilirubin which gives bile its yellow color

Ulcers

Damage to stomach lining often caused by excess acid or reduced protection

Heartburn

Acid reflux into esophagus causing irritation

Acid regulation in stomach

Body reduces HCl secretion when acidity is too high to protect tissues

Eructation

Release of gas from digestive tract through burping

Bolus

Mass of chewed food that is swallowed

Rumen

Largest compartment of ruminant stomach containing microbes for fermentation

Rumen microbes

Approximately 80 percent bacteria and 20 percent protozoa

Fermentation in ruminants

Microbial breakdown of cellulose into usable nutrients

Cellulose digestion

Humans cannot digest cellulose but ruminants can due to microbes