Essential Physiology: GI, Renal, Endocrine, and Sensory Systems
The Digestive System: Structure and Function
Functions of the digestive system include: ingestion, secretion, mixing, propulsion, digestion, absorption, and defecation.
Layers of the GI Tract Wall
- The mucosa is the innermost layer of the GI tract.
- The Serosa is the outermost layer.
- The Serosa is called the visceral peritoneum in portions of the GI tract suspended in the abdominopelvic cavity.
- The Serosa is called the Adventitia in the esophagus.
Innervation and Secretions
- The lower portion of the large
Cardiac Reentry Arrhythmias and Antiarrhythmic Drug Mechanisms
Mechanisms of Reentry Arrhythmias
The following scenarios illustrate the development of reentrant arrhythmias:
- B: Interruption of Stimulus (Prolonged Refractory Period)
This represents the momentary interruption of the stimulus due to tissue damage that prolongs the refractory period. This tissue is not dead but exhibits a lengthening of the refractory period, perhaps due to localized hypoxia (lack of oxygen). The impulse in the right branch is interrupted, but the impulse in the left branch continues
Kidney Anatomy and Urine Production Process
Kidney Anatomy and Structure
Kidneys are paired, bean-shaped organs located on the back of the abdomen, above the waist, and on both sides of the spine. Renal arteries supply blood to the kidneys, renal veins carry blood away, and ureters transport urine to the urinary bladder. From the outside, the kidney shows the following areas:
- Renal Capsule: A fibrous, clear membrane that surrounds and protects the kidney.
- Renal Cortex: The outer, dark red zone, composed of connective tissue.
- Renal Medulla: Lighter
Nephron: Kidney Structure, Function, and Regulation
The nephron is the functional unit of the kidney. Each kidney contains approximately 1 million nephrons, which do not regenerate if destroyed. From age 40, approximately 1% of nephrons are lost each year.
Components of the Nephron
The nephron is primarily formed by the glomerulus and the tubular system.
Glomerulus
An afferent arteriole, originating from the renal artery, reaches the glomerulus and branches into glomerular capillaries. These capillaries are highly permeable—approximately 400 times
Read MoreUnderstanding Red Blood Cell Indices for Anemia Diagnosis
Red Cell Indices
Red cell indices, also known as absolute values, include Mean Cell Volume (MCV), Mean Cell Hemoglobin (MCH), and Mean Cell Hemoglobin Concentration (MCHC). These are derived from hemoglobin, packed cell volume (PCV or hematocrit), and red cell count values. Automated hematology analyzers measure these indices accurately. It is crucial to correlate red cell indices with other red cell parameters like hemoglobin, hematocrit, red cell count, and other indices to rule out technical errors.
Read MorePharmacology Concepts: Receptors, Agents, and Drug Action
Partition Coefficient
The partition coefficient is the ratio of concentrations of a compound between two immiscible liquids, such as octanol and water, at equilibrium.
Bioisosteres
Bioisosteres are molecules or functional groups that have similar shapes and electronic properties, often producing similar biological effects. They can be used to modify the structure of a lead compound to improve its potency, selectivity, or pharmacokinetic properties.
Classification of Bioisosteres
- Classical Bioisosteres
- Non-