Exam 3 copy Flashcards
Neural Innervation of the GI Tract:Enteric Nervous System (ENS)
- Intrinsic set of nerves (“brain of gut”)- Neurons extending from esophagus to anus- Plexuses: myenteric plexus (GI tract motility) and submucosal plexus (controlling secretions)
Neural Innervation of the GI Tract:Autonomic Nervous System (ANS)
- Extrinsic set of nerves- Parasympathetic stimulation: increases secretion and activity by stimulating ENS.- Sympathetic stimulation: decreases secretions and activity by inhibiting ENS.
Peritoneal Folds
Peritoneal Folds
External and Internal Anatomy of the Stomach
External and Internal Anatomy of the Stomach
Chemical Digestion in the Stomach:Salivary Amylase
Salivary amylase: - digestion continues until inactivated by acidic gastric juice
Chemical Digestion in the Stomach: Lingual Lipase
Lingual lipase: - acidic gastric juice activates lingual lipase - digest triglycerides into fatty acids and diglycerides
Chemical Digestion in the Stomach:HCl
HCl - Parietal cells secrete H+ and Cl- separately but net effect is HCl- Kills many microbes, denatures proteins
Chemical Digestion in the Stomach:Pepsin
Pepsin - Secreted by chief cells - Secreted as inactive pepsinogen - Digests proteins
Chemical Digestion in the Stomach:Gastric Lipase
Gastric Lipase - Splits triglycerides into fatty acids and monoglycerides
Absorption in the Stomach
- Small amount of nutrient absorption- Some water, ions, short chain fatty acids, certain drugs (aspirin) and alcohol.
Anatomy of the Small Intestine
Anatomy of the Small Intestine
Metabollism
All chemical reactions occuring in the body.
Catabolism
Catabolism = breaking down of complex molecules.
Catabolism is exergonic—it produces more energy than it consumes.
Anabolism
Anabolism = combine simple molecules to create complex molecules
Anabolism is endergonic = consuming more energy than it produces
Overview of Cellular Respiration
Overview of Cellular Respiration
Glycolysis Reactions
Glycolysis Reactions
The Krebs Cycle is also known as…
The Krebs Cycle is also known as the citric acid cycle
Where does the Krebs cycle occur?
In the matrix of the mitochondria
What is the Krebs cycle?
A series of REDOX reactions.
What are the important processes and steps of the Krebs cycle?
- 2 decarboxylation reactions release CO2
- Reduced coenzymes (NADH and FADH2) are the most important outcome
- One molecule of ATP generated by substrate-level phosphorylation
Glycogenesis and Glycogenolysis
Glycogenesis and Glycogenolysis
Lipoproteins - How are they categorized and named?
Lipoprotiens are categorized and named according to density (ratio of lipids to proteins)
Lipoproteins - Chylomicrons
- Forms in small intestine mucosal epithelial cells
- Transport dietary lipids to adipose tissue
Lipoproteins - Very Low-Density Lipoproteins (VLDLs)
- Forms in hepatocytes
- Transport endogenous lipids to adipocytes
Low-Density Lipoproteins (LDLs)
- “bad” cholesteral
- Carry 75% of total cholesterol in blood
- Deliver to body cells for repair and synthesis
- Can deposit cholesterol in fatty plaques.
High-Density Lipoproteins (HDLs)
- “good” cholesteral
- Remove excess cholesterol from body cells and blood
- Deliver to liver for elimination
Lipid catabolism (lipolysis)
- Triglycerides split into glycerol and fatty acids
- Must be done in muscle, liver, and adipose tissue to oxidise fatty acids
- Enhanced by epinephrine and norepinephrine
Lipid anabolism (lipogenesis)
- Liver cells and adipose cells can synthesize lipids from glucose or amino acids
- Occurs when more calories are consumed than needed for ATP production.
Heat and Energy Balance - Hypothalamic thermostat is…
- Located in the preoptic area
- It is the heat-losing (cooling) center and heat-promoting (warming) center.
What functions does the kidney perform?
-
Regulation of blood ionic concentration
- (most important ions = Na+, K+, Ca2+, Cl- and HPO42- [phosphate ions])
-
Regulation of blood pH
- (via secretion of H+ into urine and conservation of HCO3- [bicarbonate ions], which are an important buffer of H+ in the blood. Normal blood pH is 7.4 +/- 0.2)
-
Regulation of blood volume
- (inc. BV = inc. in BP; kidneys inc. or dec. BV by conserving or eliminating water in the urine)
- Regulation of blood pressure
- Also:
- Maintenance of blood osmolarity
- Production of hormones (Calcitrol [the active form of vitamin D] and erythropoietin)
- Regulation of blood glucose level
- Excretion of wastes from metabolic reactions and foreign substances (drugs or toxins)
Cortical Nephrons - Overview
- Cortical nephrons comprise 80-85% of nephrons
- Renal corpuscle located in outer portion of cortex and short loops of Henle extend only into outer region of medulla
Cortical Nephrons - Flow
Cortical Nephrons - Flow
Juxtamedullary Nephrons - Overview
- Juxtamedullary nephrons comprise the other 15-20% of nephrons
- Renal corpuscle is deep in cortex and long loops of Henle extend deep into medulla
- Receive blood from peritubular capillaries and vasa recta
- Ascending limb has thick and thin regions
- Enable kidneys to secrete either very dilute or very concentrated urine.
Juxtamedullary Nephrons - Flow
Juxtamedullary Nephrons - Flow
Tubular Reabsorption
Reabsorption is the return of most of the filtered water and many solutes to the bloodstream.
- About 99% of filtered water is reabsorbed
- Proximal convoluted tubule cells make largest contribution
- Solutes are reabsorbed by both active and passive processes
Tubular Secretion
Tubular secretion is the transfer of material from blood into tubular fluid.
- Secretion of H+ helps control blood pH
- Secretion helps eliminate substances from the body
Summary of Filtration, Reabsorption and Secretion in the Nephron Collecting Duct
Summary of Filtration, Reabsorption and Secretion in the Nephron Collecting Duct
Body Fluid Compartments
Body Fluid Compartments
The body can gain water by…
The body can gain water by:
- Ingestion of liquids and moist foods (2300 mL/day)
- Metabolic synthesis of water during cellular respiration (200 mL/day)
The body can lose water through…
The body can lose water through:
- Kidneys (1500 mL/day)
- Evaporation from skin (600 mL/day)
- Exhalation from Lungs (300 mL/day)
- Feces (100 mL/day)
Intracellular Fluid (ICF) vs. Extracellular Fluid (ECF)
- ECF’s most abundant cation is Na+, anion is Cl-
- ICF most abundant cation is K+, anions are proteins and phosphates (HPO42-)
- Na+/K+ pumps play a major role in keeping K+ high inside cells and Na+ high outside cells.
Sodium (Na+)
- Most abundant ion in ECF
- 90% of extracellular cations
- Plays pivotal role in fluid and electrolyte balance because it accounts for almost half of the osmolarity of ECF
- Level in blood is controlled by:
- Aldosterone—increases renal absorption
- ADH—if sodium is too low, ADH release stops
- Atrial Natriuretic Peptide (ANP)—increases renal excretion
Bicarbonate (HCO3-)
- 2nd most prevalent extracellular anion
- Concentration increases in blood passing through systemic capillaries picking up carbon dioxide
- Carbon dioxide combines with water to form carbonic acid which dissociates
- HCO3- drops in pulmonary capillaries when carbon dioxide is exhaled
- Chloride shift helps maintain correct balance of anions in ECF and ICF
- Kidneys are main regulators of blood HCO3-
- Can form and release HCO3- when blood level is low or excrete excess to the the urine if blood level is high.
Calcium (Ca2+)
Most abundant mineral in body:
- 98% of calcium in adults is in skeleton and teeth
- In body fluids, main an extracellular cation
- Plays important roles in blood clotting, neurotransmitter release, muscle tone, and excitability of nervous and muscle tissue.
Concentration is regulated by parathyroid hormone:
- Stimulates osteoclasts to release calcium from bone—resorption
- Also enhances reabsorption from glomerular filtrate
- Increases production of calcitrol to increase absorption from GI tract
Acid-Base Balance
- Keeping H+ concentration (pH) of body fluids at an appropriate level is a major homeostatic challenge.
- 3D shape of proteins sensitive to pH
- Diets with large amounts of proteins produce more acids than bases, which acidifies blood
- Several mechanisms help maintain pH of arterial blood between 7.35 and 7.45
- Buffer systems
- Exhalation of CO2
- Kidney excretion of H+
Acid-Base Imbalances
The normal pH range of arterial blood is between 7.35 and 7.45
- Acidosis = blood pH below 7.35 (acidic)
- Alkalosis = blood pH above 7.45 (basic)
What are the major physiological effects of acid-base imbalances?
- Acidosis—results in depression of synaptic transmission in CNS
- Alkalosis—results in overexcitability of CNS and peripheral nerves
Respiratory Acidosis
Respiratory Acidosis:
- Abnormally high PCO2 in systemic arterial blood
- Cause is inadequate exhalation of CO2
- Any condition that decreases movement of CO2 out—emphysema, pulmonary edema, airway obstruction
- Kidneys can help raise blood pH
- Goal is to increase exhalation of CO2 - ventilation therapy
Respiratory Alkalosis
Respiratory Alkalosis:
- Abnormally low PCO2 in systemic arterial blood
- Cause is hyperventilation due to oxygen deficiency from high altitude or pulmonary disease, stroke, or severe anxiety.
- Renal compensation can help.
- One simple treatment: breathe into a paper bag for a short time