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Bone cells and tissues - tissue composition and cells

By: HWC, Views: 7437

Bone tissue consists of bone cells secreting bone matrix. • The extracellular bone matrix is a connective tissue that is hard, yet flexible. • Collagen fibers provide flexibility. • Inorganic mineral salts (primarily calcium phosphate, or hydroxyapatite) provide hardness. • Togethe...

Nucleic acid digestion - brush border enzymes, end products & transport mechanism

By: HWC, Views: 6443

• Further digestion occurs at the microvilli (brush border) of the epithelial cells of the villi in the small intestine. • Two brush border enzymes complete nucleic acid digestion: • Phosphatases, which catalyze the cleavage of a phosphate to form a nucleoside (nitrogenous base and pent...

Angiotensin II - kidneys, adrenal glands and dehydration

By: HWC, Views: 6835

• Angiontensin II targets cells in the proximal convoluted tubule of the nephron. ■ The reabsorption of Na+ and Cl- ions sets up an osmotic gradient favoring the retention of water. • Decreases urine production and increases blood volume and pressure. • Angiontensin II targets zon...

Medullary osmotic gradient: countercurrent multiplier, urea recycling & vasa recta countercurrent exchange

By: HWC, Views: 7369

▪ The primary cause of the medullary osmotic gradient is the active transport of solutes. • In the ascending limb of the loop, active transport of Na+ ions drives passive reabsorption of Cl- ions. • Addition of these ions to the interstitial fluid of the medulla increases its osmolarity...

Contraction cycle of a sarcomere

By: HWC, Views: 7177

• A single nervous signal releases Ca2+ ions into the sarcoplasm and initiates the contraction cycle. step 1. ATP hydrolysis • ATP provides the to move myosin molecules back into the energized configuration necessary to perform the power stroke. Step 2. Crossbridge attachment • Myosin...

Muscle Fatigue and Recovery

By: HWC, Views: 6460

• After prolonged activity, muscle contraction weakens, and the muscle enters a state of fatigue. • Fatigue results from in muscle cells, such as: • Inadequate release of calcium ions • Depletion of energy sources • Lack of oxygen • Build up of lactic acid other metabolic w...

Krebs cycle : Formation of acetyl coenzyme A and Electron transport chain

By: HWC, Views: 6785

The oxidation of glucose to produce ATP is cellular respiration. Four sets of reactions are involved: Glycolysis Formation of acetyl coenzyme A Krebs cycle reactions Electron transport chain reactions • The second pathway of glucose catabolism, formation of acetyl coenzyme A, is a transi...

Requirements for nervous signals

By: HWC, Views: 6633

• The function of neurons is to allow communication between cells, thereby maintaining homeostasis. • Electrical signals, called membrane potentials, travel along the membranes of the neurons. • Voltage variability and distance traveled determine the type of nervous signal. 1. Graded...

Import of Dietary Glucose from Intestines to Bloodstream

By: HWC, Views: 6115

• Membranes have hydrophobic interiors. which resist the passage of hydrophilic compounds and ions. • However. transporter membrane proteins facilitate the passage of these molecules. • Passive transporters accelerate diffusion of molecules towards equilibrium (decrease a concentrat...