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61 Cards in this Set
- Front
- Back
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What is the plasma of the blood.
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The intercellular matrix between the cells that the cells are in that is a fluid matrix. Has salts and plasma proteins that keep osmotic balance, buffer pH, help with clotting, and immune responses
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What are the cells in blood and what do they do
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Erythrocytes- transport oxygen and carbon dioxide. Leukocytes- destroy foreign cells, produce antibodies; roles in allergic responses
Platelets- blood clotting |
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What are platelets
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packages of enzymes and other molecules needed to seal leaks in blood vessels due to injury
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What activates a platelets to come to injury on a blood vessel
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the collagen fibers
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What happens when there is a vascular injury
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Collagen fibers are exposed activating platelets and signaling them to the site. Then the platelets swell and there is a release of clotting factors...which are other proteins that creates a plug of fibrin meshwork and blood cells to stop the leak.
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What is the difference in structure between arteries and veins?
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Arteries have thicker smooth muscle and elastic layer that when the pressure drops is can put the artery back to its original shape to help push blood along. It also has a connective tissue that allows the artery to expand when the pressure rises. Veins contain a valve that restrict blood flow to a single direction.
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What is atherosclerosis
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hardening of the arteries
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What causes atherosclerosis
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it is caused when the endothelials are damaged by prolonged high blood pressure, smoking, high fat diet, and microorganisms
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Who does atherosclerosis occur
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Plaque forms at injured enthodthelials and lipids (choloestrol) are deposited in them which makes them fatty. blood platelets stick to plaque and form embolism or blood clots.
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What are omega 3 fatty acids
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long chain fats with at least 3 double bonds which make them flexible so membranes with these fatty acids which has more fluid over a broad range of temperatures. Reduce coronary heart disease by restoring some elasticity to endothelial membranes.
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how does blood below heat get back to heart
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contractions of muscles
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what are the contractions called that forces bolus of food form mouth down esophagus to stomach
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peristalsis
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where does digestion begin for carbohydrates
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stomach
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What makes up the GI tract
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the lumen, which is covered in villi, mucosa, which connects epithelium with muscle layers, nerves, which direct contractions, and on the outside is peritoneum which anchors the GI tract in place
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What is the function of the stomach
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to hold food and allow digestion to occur more slowly than time needed to eat
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what separates the esophagus and stomach
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esophagial sphincter
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The lumenal epithelium (stomach walls) has gastric pits which to what
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hold secretory cells
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what are the secretory cells and what do they do?
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Chief cells: secrete pepsinogen
Parietal cells: secrete HCL Mucus secreting cells: Protective coating; reduces damage from acid and proteases Gastrin secreting cells: releases hormone that controls HCL and pepsinogen secretion |
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how is pepsin activated and what does it do?
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it is activated by the low pH in the stomach changing pepsinogen to pepsin. Pepsin can autocatalyze cleavage of other pepsinogen molecules to increase amount of pepsin in stomach. This is called a positive feedback
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What causes the pH of the stomach to reach less than 1
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the parietal cells generate and secrete H+ from carbonic acid
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What are the reactions that make stomach acid
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1. CO2 and H20 dissociate into H+ and HCO3.
2. The bicarbonate is actively transported out of the lumen into the blood in exchange for Cl- and Cl then moves into lumen. 3. H+ is actively transported into the lumen of the gastric pit in exchange for K+. |
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What is released out of the stomach and what controls that release
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Chyme and pyloric sphincter controls it to small intestines.
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what is chyme
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a mix of partially broken down carbohydrates and proteins, fats, DNA and acidic gastric juice.
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Where does the pyloric sphincter release the chyme
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into duodenum of small intestines
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What does the duodenum do
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it causes digestion to continue with help of liver and pancreas. Digests dietary fats when bile, which is made in the liver a
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what do the jejunum and ileum do
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absorb nutrients
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how does the duodenum digest fat
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Digests dietary fats when bile, which is made in the liver and stored in gall bladder, secretes into the duodenum and emulsifies the fat. The enzymes that break down the fat are lipases, which are secreted by the pancreas
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How are proteins digested in the duodenum
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the pancreas secretes trypsinogen to further break down peptides from the stomach. It a secretes basic fluid to neutralize the acidic chime
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How are carbohydrates digested in the duodenum
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digested to monosaccharides through action of pancreatic amylase and he enzymes maltase, lactase, and sucrase found in duodenum
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How is DNA digested in the duodenum
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Pancreatic nucleases break down DNA molecules into nucleotides which are recycled into DNA and RNA synthesis rather than broken down further
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Where do he sugars and amino acids go after being absorbed in small intestines
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delivered to liver to make energy or build new molecules
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where are fats delivered to after absorption in small intestines
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delivered to tissues for energy, membrane synthesis and storage
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why do fats pose a challenge for digestion
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they are hydrophobic
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how does the large lipid droplet broken down
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it is slubilized by bile in the duodenum to form bile and triglyceride micelles
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what happens after micelles are made from the large lipids
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Micelles are substrates for pancreatic lipases which breakdown triglycerides to fatty acids and monoglycerides
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how do monoglycerides (fattly acid bound to glycerol) and fatty acids get to epithelial cell
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diffuse across the villi and are reassembled into tryglycerides in the intestinal cell
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what happens after monoglycerides and fatty acids are reassembled into tryglycerides in the intestinal cell
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they are packaged with proteins to become the lipoproteins know as chylomicrons
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What do chylomicrons do
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they are exocytosed into the lymphatic system until being transferred to the blood in the thoracic vein in the neck where they circulate, delivering fats and cholesterol to the tissues.
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Chylomicrons turn into what after delivering lipids and does what?
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VLDL then LDL the HDL which returns to the liver where the cholesterol can be made into bile and steroid hormones
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what synthesizes bile
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crabohydrates
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what does gastrin do and when is it inhibited.
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It is a digestive hormone that is released when there is food in the stomach and it circulates the blood and stimulates the secretion of HCl and perpsin and stimulates movements in the stomach
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What do cholecysokinin do and when are they released
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they are digestive hormones that cause the release of bile from gallbadder to emulsify fats and stimulates release of digestive enzymes from the pancreas. IT is realsed when undigested fats and proteins in chyme go to small intestines.
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What do secretin do and when are they released
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they are digestive enzymes that release bicarbonate solution from pancreas to neutralize acids. It is released by the acid in chyme.
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what is the structure of a muscle
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has man muscle fibers which are single celled multinuclear and are very long
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What is muscle contraction due to
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the interaction between contractile proteins actin and myosin
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what are myofibrils
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bundles of thin actin and thick myosin filaments arranged in an orderly fashion
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what are sarcomeres
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what makes up myofibrils. made of overlapping filaments of actin and myosin creating pattern
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what is titin
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protein that hold bundles of myosin filaments in a centered position within the sarcomere
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what makes up a muscle fiber cell
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sarcolemma (plasma membrane), sarcoplasm, multiple nuclei
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what makes up sarcoplasm
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sarcoplasmic reticulum, myofibrils, sarcoplanm
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what makes up myofibrils
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troponin, actin, tropomyosin myosin and titin
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actin filaments, myosin, titin make up what
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a sarcomere
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what are actin filaments composed of
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3 proteins actin, troponin and tropomyosin
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what are myosin filaments composed of
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myosin and titin
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what are the steps for a muscle to contract
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action potential arrives at motor neuron terminal and goes down t tubule of muscle. this causes the release of Ca2+ from the sarcoplasmic reticulum which diffuses in the sarcoplasm which causes a muscle contraction
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what are all muscles fibers activated by
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a motor unit
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when does a muscle contraction stop
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when Ca2+ is pumped back into the sarcoplasmic reticulum
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what is tropomyosin
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two stranded protein between lying in the grooves of the actin filament
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what is troponin
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globular protein on the actin filaments. it has 3 subunits the bind actin, bind tropomyosin and bind Ca2+.
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how does he myosin head bind the actin filaments
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when Ca2+ is released is binds to troponin which is binded to tropomyosin, which blockes the head of the myosin but troponin then move is so myosin can bind.
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what is on the head of the myosin filament that causes the slide between myosin and actin
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ADP + Pi and it releases Pi from head causing power stroke and the filaments slide past one another. The ADP is released and ATP is picked up causing myosin to release from actin. then atp is hydrolyzed causing myosin to return to its extended conformation.
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