SBI 3U1 Internal Systems Practice Flashcards

A comprehensive set of vocabulary flashcards based on the Internal Systems unit notes, covering biology concepts related to nutrition, digestion, respiration, and circulation.

Nutrient

Any substance that has a useful function when taken up by the body cells; includes carbohydrates, proteins, fats, water, vitamins, and minerals.

Macronutrient

Nutrients needed by the body in large amounts daily, specifically carbohydrates, fats, and proteins (macromolecules).

Micronutrient

Nutrients needed by the body in small quantities daily, such as vitamins and minerals; absence can lead to deficiency diseases like Scurvy.

Essential Nutrients

Nutrients that must be obtained from the diet because the body cannot synthesize them, such as certain amino acids and fatty acids.

Polymer

A macromolecule made up of repeating units or long chains of smaller subunits called monomers.

Monomer

The smallest subunit of a macromolecule.

Alimentary Canal

A canal extending from the mouth to the anus, approximately $7-9\,m$ long, through which food passes during digestion; also known as the gastrointestinal tract.

Accessory Organs

Glands joined to the alimentary canal by ducts that provide enzymes and other substances essential for digestion, such as the liver and pancreas.

Ingestion

The first step of the digestive process involving taking food into the body by the mouth.

Mechanical Digestion

The physical breakdown of food into smaller parts without chemical change, involving the mouth and muscular churning of the stomach.

Chemical Digestion

The breakdown of food into particles small enough to be absorbed into the bloodstream using enzymes and digestive juices.

Enzyme

A protein that acts as a biological catalyst, speeding up the rate of a biological reaction without being used up.

Bolus

A soft mass of food molded and smoothed by the tongue that is pushed to the back of the throat to begin the swallowing process.

Peristalsis

The process of involuntary muscle contractions that allow food to move down the esophagus and other parts of the digestive tract.

Rugae

Folded long ridges in the inner muscle layer of the stomach that allow it to expand and increase surface area.

Gastrin

A hormone that stimulates the release of gastric juice, which consists of hydrochloric acid and enzymes, from gastric cells in the stomach.

Chyme

The semi-liquid state of food as it leaves the stomach through the pyloric sphincter.

Villi

Finger-like projections on the inner surface of the small intestine that increase surface area for nutrient absorption.

Lacteals

Lymph vessels found within each villus that specifically absorb digested lipids.

Bile

A mixture of salts, acids, and cholesterol produced by the liver that emulsifies fats; it is stored in the gallbladder.

Insulin

A hormone secreted by the pancreas that allows glucose to enter cells, thereby decreasing blood glucose levels; normal range is $4-7\,mmol/L$.

Glucagon

A hormone secreted by the pancreas that works in opposition to insulin to raise blood glucose levels.

Homeostasis

The ability or tendency of an organism to maintain internal stability to compensate for environmental changes.

Pharynx

The location where inhaled air from the nasal cavity meets inhaled air from the mouth; it is a common path for air and food.

Epiglottis

A structure that covers the trachea when eating to prevent food from entering the windpipe and causing choking.

Alveoli

Tiny grape-like bunches of air sacs in the lungs where oxygen and carbon dioxide are exchanged with the bloodstream.

Tidal Volume (TV)

The amount of air that passes in and out of the lungs with each normal breath, typically between $250-500\,mL$.

Vital Capacity (VC)

The maximum amount of air that can be moved into and out of the respiratory system, approximately $4500\,mL$.

External Respiration

The phase of respiration where $O_2$ and $CO_2$ are exchanged between the alveoli and the capillaries on the surface of the alveoli.

Cellular Respiration

The chemical process in the cytosol and mitochondria represented by the equation: $O_2 + C_6H_{12}O_6 \rightarrow CO_2 + H_2O + \text{Energy (ATP)}$.

Plasma

The straw-coloured liquid component of blood, making up about 55% of blood volume, consisting of 92% water and 7% plasma proteins.

Erythrocytes

Red blood cells (RBCs) that are tiny, biconcave, lack a nucleus at maturity, and transport $O_2$ and $CO_2$ using hemoglobin.

Leukocytes

White blood cells (WBCs) that are colourless, contain a nucleus, and are responsible for fighting infection.

Thrombocytes

Also known as platelets, these are tiny cell fragments produced in bone marrow that facilitate blood clotting.

Antigen

Special proteins or markers on the surface of red blood cells that determine major human blood types (A, B, AB, and O).

Agglutination

The clumping together of red blood cells caused by an antigen-antibody reaction when different blood types are mixed.

Rh Factor

Also called the D antigen, this is a protein on the surface of red blood cells used to determine Rh positive ($Rh+$) or Rh negative ($Rh-$) status.

Arteries

Thick-walled blood vessels that carry oxygen-rich blood away from the heart at high pressure, except for the pulmonary artery.

Capillaries

Smallest blood vessels with walls only one cell thick, serving as the site for exchange of oxygen, nutrients, and waste between blood and body cells.

Veins

Thinner-walled blood vessels with one-way valves that carry carbon dioxide-rich blood toward the heart under low pressure.

Septum

The muscular wall that separates the right side of the heart (oxygen-poor blood) from the left side (oxygen-rich blood).

Systemic Circuit

The pathway of vessels that moves blood from the heart to the body tissues and back to the heart.

Pulmonary Circuit

The pathway of vessels that moves blood from the heart to the lungs and back to the heart.

Diastole

The period of the cardiac cycle characterized by heart muscle relaxation and the filling of the heart with blood.

Systole

The period of the cardiac cycle characterized by heart muscle contraction and the emptying of blood from the heart.

Sinoatrial (SA) Node

A mass of nerve tissue in the right atrium that initiates and controls the heartbeat, acting as the heart's pacemaker.

Hypertension

A condition where blood pressure is consistently above normal, typically defined as systolic pressure $> 140\,mmHg$ or diastolic pressure $> 90\,mmHg$.