Anatomy and Physiology Practice Flashcards

Comprehensive practice vocabulary flashcards covering pH balance, bone anatomy, joint classification, muscle physiology, and the digestive system based on lecture notes.

Normal Blood pH

Maintained between $7.35$ and $7.45$ through the actions of the kidneys and lungs.

Acidosis

A physiological state resulting from abnormally low blood pH, specifically referred to as acidemia when blood pH is below $7.35$.

Alkalosis

A physiological state resulting from abnormally high blood pH, specifically referred to as alkalemia when blood pH is above $7.45$.

Fixed Acids

Acids like sulfuric and phosphoric acid that do not leave solution and remain in body fluids until eliminated by the kidneys.

Volatile Acids

Acids that can leave the body by entering the atmosphere at the lungs, such as carbonic acid which breaks down into carbon dioxide ($CO_2$) and water ($H_2O$).

Carbonic anhydrase

An enzyme found in red blood cells, liver, kidney, and stomach parietal cells that catalyses the formation of carbonic acid from $CO_2$ and $H_2O$.

Phosphate buffer system

Consists of $H_2PO_4$ (a weak acid) and its anion $HPO_4^{2-}$; it is important for buffering the pH of the ICF and urine.

Chloride shift

The process where bicarbonate ions diffuse into plasma from red blood cells in exchange for chloride ions.

Respiratory compensation

A change in respiratory rate that helps stabilize the pH of the ECF by affecting the carbonic acid-bicarbonate buffer system.

Haematopoiesis

The process of blood cell production, including WBCs, RBCs, and platelets, which occurs in the red bone marrow of spongy bone.

Periosteum

The outer layer of membrane surrounding bone that is responsible for blood supply, fracture repair, and serves as an attachment point for ligaments and tendons.

Osteoblasts

Specialized bone cells that secrete unmineralized bone matrix or develop into osteocytes.

Osteocytes

Mature forms of osteoblasts that reside in lacunae and maintain the bone matrix while responding to stimuli like increased force.

Osteoclasts

Giant multinuclear cells with ruffled borders that function in bone resorption by breaking down or melting bone.

Osteons

Repeated structural units of compact bone composed of concentric lamellae containing blood vessels and nerves.

Canaliculi

Small channels filled with extracellular fluid that connect lacunae and allow communication and nutrient/waste exchange between osteocytes.

Axial Skeleton

The 80 bones making up the long axis of the body.

Appendicular Skeleton

The 126 bones consisting of the upper and lower limbs.

Synovial joints

Freely movable (diarthrotic) joints characterized by a fluid-filled cavity, articular cartilage, and a joint capsule.

Articular discs (menisci)

Fibrocartilage that separates articular surfaces to improve fit, stabilize joints, and provide shock absorption.

First-Class Lever

A lever system where the fulcrum is positioned between the load and the effort.

Excitability

A main characteristic of muscle tissue defined as the ability to receive and respond to stimuli.

Motor unit

Consists of a single motor neuron and all the muscle fibres it supplies.

Acetylcholine (ACh)

The neurotransmitter released at the neuromuscular junction (NMJ) that binds to receptors on the sarcolemma to initiate muscle contraction.

Sarcomere

The smallest functional contractile unit of a muscle, consisting of the area between two Z discs.

Isometric contraction

A contraction where muscle tension increases but the muscle does not shorten because the tension does not exceed the load.

Isotonic contraction

A contraction where the muscle shortens because the muscle tension exceeds the load.

Muscle hypertrophy

An increase in muscle fibre size resulting from resistance exercise, leading to more mitochondria, myofilaments, and glycogen stores.

Peristalsis

Continuous segments of contraction and relaxation that move food through the GI tract, primarily in the oesophagus.

Segmentation

Nonadjacent segments of the GI tract contracting and relaxing to mechanically break down food, primarily occurring in the small intestine.

Myenteric plexus

Part of the enteric nervous system located between smooth muscle layers that controls GI tract motility and contraction strength.

Submucosal plexus

Part of the enteric nervous system that controls secretions within the gastrointestinal tract.

Parietal cell

Stomach cells that release hydrochloric acid ($HCl$) to create pepsin and factor in the formation of peptides.

Rugae

Large folds formed by the stomach mucosa when the organ is empty.

Chyme

The paste-like substance produced when the stomach converts a bolus of food through gastric activity.

Hepatic portal vein

The vessel in the portal triad that brings nutrient-rich blood from the intestines to the liver lobules.

Villi

Finger-like projections of the small intestine mucosa that contain capillary beds and lacteals for nutrient absorption.

Brush border enzymes

Membrane-bound enzymes on microvilli (like maltase and lactase) that perform the final digestion of carbohydrates and proteins.

Caecum

The small pouch at the beginning of the large intestine, located inferior to the ileocecal valve.

Defecation reflex

Triggered by the distension of the rectal wall, which stimulates stretch receptors and initiates parasympathetic motor impulses for elimination.