Daras + me health science take two

Cardiovascular System

The system consisting of the heart and blood vessels that circulates blood throughout the body.

Heart Anatomy

Muscular, four-chambered organ (two atria, two ventricles); walls made of cardiac muscle (myocardium); contains valves to prevent backflow.

Heart Function

Acts as a pump to circulate blood throughout the body — right side pumps deoxygenated blood to the lungs (pulmonary circulation); left side pumps oxygenated blood to the rest of the body (systemic circulation).

Arteries Structure

Thick, muscular, and elastic walls; small lumen; no valves (except in pulmonary artery and aorta).

Arteries Function

Carry blood away from the heart under high pressure; elasticity allows them to expand and recoil with each heartbeat.

Veins Structure

Thinner, less muscular walls; large lumen; contain valves to prevent backflow.

Veins Function

Carry blood toward the heart under low pressure; valves and skeletal muscle contractions help return blood to the heart.

Capillaries Structure

Extremely thin walls (one cell thick); form vast networks between arteries and veins; narrow lumen.

Capillaries Function

Site of exchange of gases, nutrients, and wastes between blood and tissues by diffusion; thin walls allow rapid exchange.

Cardiac Cycle

The sequence of events that occur in the heart during one complete heartbeat.

Diastole

Phase when the heart muscle relaxes, allowing chambers to fill with blood.

Systole

Phase when the heart muscle contracts in the ventricles to pump blood out of the heart.

Gas Exchange

Occurs in the alveoli of the lungs, where oxygen and carbon dioxide are exchanged between the air and the blood.

Inhalation

The diaphragm contracts and moves downward, and the intercostal muscles lift the rib cage up and out, increasing the volume of the chest cavity.

Exhalation

The diaphragm relaxes and moves upward, and the rib cage moves down and in, decreasing the volume of the chest cavity.

Stroke Volume (SV)

The amount of blood pumped by the left ventricle in one contraction (heartbeat); reflects how effectively the heart pumps with each beat.

Cardiac Output

The total volume of blood pumped by the heart per minute, which is influenced by stroke volume and heart rate.

Saturated O2

The maximum amount of oxygen that can be carried by hemoglobin in the blood, usually expressed as a percentage.

Lung Volume/Capacity

The total amount of air that the lungs can hold, which includes various measurements such as tidal volume, vital capacity, and residual volume.

Health Vitals

Measurements of the body's basic functions, including heart rate, blood pressure, respiratory rate, and temperature.

Altitude Training Simulation

Training method that involves exercising in conditions of reduced oxygen availability to enhance athletic performance.

Congestive Heart Failure

A condition in which the heart is unable to pump sufficiently to maintain blood flow to meet the body's needs.

Asthma

A chronic respiratory condition characterized by episodes of airway obstruction, leading to difficulty in breathing.

Blood Composition

The components of blood, including red blood cells, white blood cells, platelets, and plasma.

Blood Typing

The classification of blood based on the presence or absence of specific antigens on the surface of red blood cells.

Transfusions

The process of transferring blood or blood components from one person to another.

Therapies for Respiratory Diseases

Treatment methods aimed at managing and alleviating symptoms of respiratory conditions.

Therapies for Cardiovascular Diseases

Treatment methods aimed at managing and alleviating symptoms of cardiovascular conditions.

Cardiac Output (CO)

The volume of blood the heart pumps per minute, measured in L/min, normal range: around 4 - 8 L/min.

Factors affecting heart rate

Includes autonomic innervation, hormones, fitness level, and age.

Factors affecting stroke volume

Includes heart size, fitness level, genders, contractility, duration of contraction, preload (EDV), and afterload (resistance).

Nose / nasal cavity

Structure: openings at the front of the face leading to nasal passages lined with mucus and tiny hairs (cilia). Function: filters, warms, and moistens incoming air.

Pharynx (throat)

Structure: muscular tube connecting nasal cavity and mouth to larynx and oesophagus. Function: passageway for air and food.

Larynx (voice box)

Structure: cartilage structure containing vocal cords. Function: produces sound, prevents food entering trachea.

Trachea (windpipe)

Structure: flexible tube supported by C-shaped cartilage rings. Function: allows air passage to bronchi; cartilage keeps it open.

Bronchi

Structure: two main branches from the trachea entering each lung, with smaller branches inside the lungs. Function: directs air into each lung; lined with mucus and cilia to trap dust and microbes.

Bronchioles

Structure: small, branching tubes from the bronchi, ending in alveoli. Function: distribute air throughout the lungs.

Alveoli

Structure: tiny sacs with thin walls surrounded by capillaries; millions in each lung. Function: site of gas exchange (oxygen into blood, carbon dioxide out).

Lungs

Structure: two spongy organs in the chest cavity, protected by the rib cage. Function: house bronchi, bronchioles, and alveoli; allow gas exchange.

Diaphragm

Structure: dome-shaped muscle below the lungs. Function: contracts to increase chest volume during inhalation; relaxes for exhalation.

Intercostal muscles

Structure: external and internal muscles between ribs. Function: external intercostals lift ribs during inhalation; internal intercostals lower ribs during forced exhalation.

Pleura

Structure: double-layered membrane surrounding each lung with fluid in between. Function: reduces friction during breathing movements.

Pulmonary capillaries

Structure: network of tiny blood vessels surrounding alveoli. Function: carry deoxygenated blood to alveoli and oxygenated blood back to the heart.

SA Node

Structure: upper wall of the right atrium, near the opening of the superior vena cava. Function: initiates electrical impulses and sets the pace of the heartbeat.

AV Node

Structure: at the junction of the atria and ventricles in the interatrial septum. Function: receives impulses from SA node and delays signal to ventricles.

Purkinje Fibers

Structure: subendocardial layer of both ventricles (extend from the bundle branches through ventricular walls). Function: rapidly conduct impulses throughout ventricles and trigger ventricular contraction.

Surface area to volume ratio

Compares how much surface a cell has relative to its internal volume; important because the surface area controls how much material can enter or leave the cell, while the volume determines how much the cell needs.

Change in surface area to volume ratio as a cell grows

As a cell grows, its volume increases faster than its surface area, leading to a decrease in the surface area to volume ratio, making it harder for the cell to exchange materials efficiently.

Smaller Cells Diffusion Efficiency

Smaller cells have a higher surface area to volume ratio, allowing for quicker diffusion of oxygen, nutrients, and waste.

Low Surface Area to Volume Ratio

Cells with a low SA:V have less surface area for diffusion, causing substances to take longer to reach the center and slowing the exchange rate.

Specialised Structures in Large Organisms

Large organisms require structures like lungs for gas exchange due to their low overall SA:V ratio, which is insufficient for simple diffusion.

Benefits of High Surface Area to Volume Ratio

A high SA:V ratio increases diffusion rates, aiding in the quick exchange of gases, nutrients, and wastes, supporting faster metabolism.

Role of Diffusion in Cells

Diffusion allows molecules to move from high to low concentration, enabling cells to absorb oxygen and nutrients while removing waste.

Red Blood Cells and Surface Area

Red blood cells have a biconcave shape that provides a high surface area to volume ratio, facilitating quick diffusion of gases.

Tidal Volume (TV)

The amount of air inhaled or exhaled in a normal breath.

Inspiratory Reserve Volume (IRV)

The additional volume of air inhaled after a normal inhalation.

Expiratory Reserve Volume (ERV)

The additional volume of air exhaled after a normal exhalation.

Residual Volume (RV)

The air remaining in lungs after a maximal exhalation that cannot be voluntarily exhaled.

Vital Capacity (VC)

The maximum amount of air exhaled after a maximum inhalation, calculated as VC = TV + IRV + ERV.

Total Lung Capacity (TLC)

The total volume of air the lungs can hold after maximum inhalation, calculated as TLC = VC + RV.

Inspiratory Capacity (IC)

The maximum amount of air inhaled after a normal exhalation, calculated as IC = TV + IRV.

Functional Residual Capacity (FRC)

The volume of air remaining in lungs after a normal exhalation, calculated as FRC = ERV + RV.

Obesity

A risk factor for cardiovascular conditions.

Smoking

A risk factor for cardiovascular conditions.

Alcohol/drug abuse

A risk factor for cardiovascular conditions.

Family history of cardiovascular conditions

A risk factor for cardiovascular conditions.

Diabetes

A risk factor for cardiovascular conditions.

High blood pressure

A risk factor for cardiovascular conditions.

Coronary heart disease

A risk factor for cardiovascular conditions.

Age

More common in older adults as a risk factor for cardiovascular conditions.

Heart attack

A cause of cardiovascular conditions.

Congenital heart defects

A cause of cardiovascular conditions.

Hypertension

High blood pressure, a cause of cardiovascular conditions.

Cardiomyopathy

Weakened heart muscle, a cause of cardiovascular conditions.

Various valve diseases

A cause of cardiovascular conditions.

Changes in urination frequency

A symptom of cardiovascular conditions.

Swelling in abdominal cavity/region

A symptom of cardiovascular conditions.

Shortness of breath

Particularly when lying down, a symptom of cardiovascular conditions.

Swelling in the legs, ankles and feet

A symptom of cardiovascular conditions.

Persistent cough

A symptom of cardiovascular conditions.

Wheezing

A symptom of cardiovascular conditions.

Fatigue

A symptom of cardiovascular conditions.

Weakness

A symptom of cardiovascular conditions.

Physical exam

A method of diagnosis for cardiovascular conditions.

Chest x-ray

A method of diagnosis for cardiovascular conditions.

Blood test

A method of diagnosis for cardiovascular conditions.

ECG

A method of diagnosis for cardiovascular conditions.

Diuretics

Medicinal treatment that removes excess fluid.

Beta blockers

Medicinal treatment that lowers blood pressure.

Low salt diet

A non-medicinal treatment for cardiovascular conditions.

Exercise

A non-medicinal treatment for cardiovascular conditions.

Weight loss

A non-medicinal treatment for cardiovascular conditions.

Reduce stress

A non-medicinal treatment for cardiovascular conditions.

Reducing or quitting smoking/alcohol/drugs

A non-medicinal treatment for cardiovascular conditions.

Altitude training

How people train or live at high altitudes where the air has less available oxygen.

Athletes training at high altitudes

Forces the body to produce more red blood cells and hemoglobin to carry oxygen more efficiently.

Altitude simulation masks

Used by athletes to mimic low-oxygen conditions without leaving sea level.

People in high-altitude regions

Have developed long-term genetic and physiological adaptations to thin air.

Chronic Obstructive Pulmonary Disease (COPD)

Condition that worsens at high altitudes due to lower air pressure and oxygen levels.

Supplemental oxygen

Often necessary for people with COPD at high altitudes.