BIO-211 - Lecture Test 2

Anastomoses

Connections between blood vessels that allow alternate routes for blood flow

Bradycardia

Abnormally slow heart rate (<60 bpm)

Tachycardia

Abnormally fast heart rate (>100 bpm)

Angina pectoris

Chest pain due to transient ischemia (reduced blood flow) to the myocardium

Cardiac tamponade

Compression of the heart due to fluid accumulation in the pericardial sac

Pericarditis

Inflammation of the pericardium (heart’s outer covering)

Ductus arteriosus

Fetal vessel connecting the pulmonary artery to the aorta; bypasses lungs before birth

Ligamentum arteriosum

Adult remnant of the ductus arteriosus

Auricles

Small ear-like appendages on atria that increase atrial volume

Pectinate muscles

Ridges of myocardium in the atrial walls (especially right atrium)

Fossa ovalis

Depression in the interatrial septum; remnant of the foramen ovale

Foramen ovale

Fetal opening between right and left atria allowing blood to bypass lungs before birth

Trabeculae carneae

Irregular muscular ridges on inner ventricular walls

Valvular prolapse

When a valve cusp bulges backward into the previous chamber, possibly allowing regurgitation

Myocardial infarction

Death of heart tissue due to prolonged ischemia (heart attack)

Chronotropic (positive)

Increases heart rate (e.g., epinephrine, SNS)

Chronotropic (negative)

Decreases heart rate (e.g., acetylcholine, PNS)

Inotropic (positive)

Increases force of contraction (e.g., digitalis, SNS)

Inotropic (negative)

Decreases force of contraction (e.g., acidosis, PNS)

Congestive heart failure

Heart’s pumping ability is weakened, leading to fluid accumulation

Cardiac reserve

Difference between resting and maximum cardiac output

Baroreceptors

Pressure sensors in carotid sinuses and aortic arch that help regulate BP

Chordae tendineae

Tendinous cords anchoring AV valve flaps to papillary muscles

Papillary muscles

Muscles in ventricles that anchor chordae tendineae and prevent valve prolapse

Preload

The degree of stretch of the heart muscle (ventricles) before contraction; it reflects the amount of blood returning to the heart (end-diastolic volume)

Afterload

The pressure or resistance the ventricles must overcome to eject blood during systole; mainly determined by arterial blood pressure and vessel resistance

Contractility

The intrinsic strength of the heart muscle independent of preload and afterload; it reflects how forcefully the heart contracts at a given preload

Autorhythmicity of the heart

The ability of the heart to generate its own electrical impulses without needing stimulation from the nervous system

Haldane effect

The phenomenon where oxygen binding to hemoglobin reduces hemoglobin’s ability to carry carbon dioxide

Aneurysm

A weak, bulging area in the wall of a blood vessel (usually an artery) that may rupture and cause internal bleeding

Artery

A blood vessel that carries blood away from the heart; usually carries oxygenated blood (except pulmonary arteries)

Vein

A blood vessel that carries blood toward the heart; usually carries deoxygenated blood (except pulmonary veins)

Precapillary sphincters

Rings of smooth muscle at the entrance to capillary beds that control blood flow into individual capillaries

Portal systems

Networks of two capillary beds connected by a vein, allowing blood to pass through two exchange sites (e.g., hepatic portal system)

Perfusion

The flow of blood through tissues to deliver oxygen and nutrients and remove waste products

Mean arterial pressure (MAP)

The average pressure in the arteries during one cardiac cycle; indicates overall tissue perfusion pressure

Systolic pressure

The maximum arterial pressure during ventricular contraction (systole)

Diastolic pressure

The minimum arterial pressure during ventricular relaxation (diastole)

Orthostatic hypotension

A sudden drop in blood pressure when standing up quickly, often causing dizziness or lightheadedness

Hypotension

Abnormally low blood pressure, which may result in poor tissue perfusion

Hypertension

Abnormally high blood pressure, increasing the risk of heart disease, stroke, and vascular damage

Frank-Starling law of the heart

The principle that the greater the stretch of the cardiac muscle fibers (during filling or preload), the stronger the force of contraction and the greater the stroke volume

Hypothalamus

Regulates breathing rate in response to emotional states, stress, and temperature changes. It connects the respiratory system to emotional and physiological reactions, such as increased breathing during fear or anxiety

Medulla Oblongata

Contains the main respiratory control centers — the dorsal and ventral respiratory groups. It monitors blood CO₂ and pH levels and automatically adjusts the rate and depth of breathing to maintain homeostasis

Pons

Works with the medulla to fine-tune and smooth the breathing rhythm. It coordinates the transition between inhalation and exhalation and helps prevent over-inflation of the lungs

Baroreceptor

Specialized pressure-sensitive sensory receptors located mainly in the carotid sinuses and aortic arch. They detect changes in blood pressure and send signals to the medulla oblongata to help regulate heart rate and breathing

Why are veins called high-capacitance vessels?

They can hold a large volume of blood at low pressure

Coronary circulation

The circulation of blood to the heart muscle (myocardium) itself. Coronary arteries supply the heart tissue with oxygen and nutrients, while coronary veins remove carbon dioxide and waste. This ensures the heart has the energy it needs to continuously pump blood throughout the body.

Biggest concern during ischemia in the heart – Oxygen

The most critical concern during ischemia is a lack of oxygen. The heart muscle relies almost entirely on aerobic metabolism to produce ATP. Without enough oxygen, energy production drops rapidly, leading to cell injury or death and potentially a heart attack (myocardial infarction)

Biggest concern during ischemia in the heart – Nutrients

During ischemia, the supply of nutrients such as glucose and fatty acids is also reduced because of decreased blood flow. This limits the availability of fuel for energy production, further stressing the heart muscle — although the lack of oxygen remains the most critical issue

Conduction Zone

The part of the respiratory system that transports air to and from the lungs but does not participate in gas exchange. It includes the nose, pharynx, larynx, trachea, bronchi, and bronchioles. Its main functions are to filter, warm, and humidify incoming air

Respiratory Zone

The region of the respiratory system where gas exchange occurs between air and blood. It includes the respiratory bronchioles, alveolar ducts, and alveoli. Oxygen diffuses into the blood while carbon dioxide diffuses out during respiration

Alveolar Ventilation Rate (AVR) formula

AVR=(Tidal Volume−Dead Space Volume)×Respiratory Rate

Mucociliary escalator

is a crucial defense mechanism in the respiratory tract. It consists of mucus-producing cells that trap dust, pathogens, and debris, and cilia that move the mucus upward toward the throat, where it can be swallowed or expelled. This process helps keep the airways clear, protects the lungs from infection and irritation, and maintains healthy respiratory function

Cardiac Center

located in the medulla oblongata, regulates heart rate and contractility. It has two parts: the cardioacceleratory center, which increases heart rate and force of contraction through the sympathetic nervous system, and the cardioinhibitory center, which decreases heart rate through the parasympathetic (vagus) nerve. Together, they help maintain stable blood pressure and cardiac output

Vasomotor Center

located in the medulla oblongata, controls the diameter of blood vessels by regulating smooth muscle in the vessel walls. It maintains vascular tone and blood pressure by causing vasoconstriction (increased sympathetic activity) or vasodilation (decreased sympathetic activity)

Tidal Volume (TV)

The amount of air inhaled or exhaled during a normal, quiet breath. It represents the basic volume of air exchanged with each breath. About 500 mL in a healthy adult

Vital Capacity (VC)

The maximum amount of air a person can exhale after a maximum inhalation. It includes tidal volume, inspiratory reserve volume, and expiratory reserve volume (VC = TV + IRV + ERV). About 4,800 mL in adults (varies by age, sex, and body size

Importance of calcium in the heart

is needed for the heart to contract and beat properly. It helps heart muscle cells shorten during each heartbeat and also affects the strength and rhythm of contractions. Too little or too much calcium can cause irregular heartbeats or weak pumping

Hypovolemic Shock

Caused by a loss of blood or body fluids (e.g., from bleeding, dehydration, or burns). Leads to low blood volume, decreased venous return, and reduced cardiac output

Cardiogenic Shock

Caused by the heart’s inability to pump blood effectively (e.g., after a heart attack or severe heart failure). Results in low cardiac output despite normal blood volume

Obstructive Shock

Caused by a physical blockage that prevents normal blood flow, even though the heart and blood volume are normal. This obstruction reduces cardiac output and leads to inadequate tissue perfusion

Vascular (Distributive) Shock

Caused by widespread vasodilation, leading to a drop in blood pressure even though blood volume is normal. Common types are septic, neurogenic, and anaphylactic

Central Chemoreceptors and Breathing

Located in the medulla oblongata, these chemoreceptors detect changes in CO₂ and pH levels in the cerebrospinal fluid. When CO₂ levels rise or pH drops (more acidic), they signal the brain’s respiratory centers to increase breathing rate and depth to remove excess CO₂

Peripheral Chemoreceptors and Breathing

Found in the carotid bodies and aortic bodies, these chemoreceptors monitor O₂, CO₂, and pH in the blood. When O₂ levels drop, or when CO₂ rises/pH falls, they send signals to the medulla to increase ventilation and restore normal gas levels

Asthma

Chronic inflammation and narrowing of the airways, causing wheezing and shortness of breath

Chronic Obstructive Pulmonary Disease (COPD)

Long-term obstruction of airflow, usually due to chronic bronchitis or emphysema; makes breathing difficult

Chronic Bronchitis

Inflammation of the bronchi with excess mucus production; causes persistent cough

Emphysema

Damage to alveoli reduces surface area for gas exchange, causing shortness of breath

Pneumonia

Infection that inflames the alveoli, which may fill with fluid or pus

Tuberculosis (TB)

Bacterial infection (Mycobacterium tuberculosis) that mainly affects the lungs

Lung Cancer

Uncontrolled cell growth in lung tissue; often caused by smoking

Pulmonary Fibrosis

Scarring of lung tissue that reduces elasticity and gas exchange

Pulmonary Edema

Fluid buildup in the alveoli, often due to heart failure

Pneumothorax

Air in the pleural cavity causing lung collapse

Atelectasis

Partial or complete collapse of a lung or lobe due to blocked airways or pressure

Cystic Fibrosis

Genetic disorder causing thick mucus that clogs lungs and digestive tract

Sleep Apnea

Repeated pauses in breathing during sleep

Respiratory Distress Syndrome (RDS)

Seen in premature infants due to lack of surfactant; makes breathing difficult

ARDS (Acute Respiratory Distress Syndrome)

Sudden, severe inflammation and fluid buildup in the alveoli, often due to trauma or infection

Airway Resistance

The opposition to airflow caused by friction between air and the walls of the airways

Airway Diameter

The main factor affecting resistance — smaller diameter = higher resistance, larger diameter = lower resistance

Bronchoconstriction

Narrowing of the airways (e.g., from asthma, histamine, or parasympathetic activity) → increases resistance and decreases airflow

Bronchodilation

Widening of the airways (e.g., from sympathetic stimulation or epinephrine) → decreases resistance and increases airflow

Lung Elasticity

Loss of elasticity (as in emphysema) can reduce passive exhalation and alter airflow

Air Viscosity

Thicker air (like at high altitude or humidity) slightly increases resistance, though effect is minor

Relationship Summary

Flow = Pressure / Resistance — higher resistance = lower airflow

Hemoglobin (Hb)

A protein in red blood cells that binds oxygen in the lungs and releases it in tissues

Function of Hemoglobin

Transports most of the oxygen in the blood; each molecule can carry 4 O₂ molecules (one per heme group)

Oxyhemoglobin

Hemoglobin bound to oxygen (HbO₂)

Deoxyhemoglobin

Hemoglobin that has released its oxygen

Loading of Oxygen

Occurs in the lungs when oxygen binds to hemoglobin

Factors that Enhance O₂ Loading (Binding)

- High PO₂ (oxygen pressure) in lungs
- Cool temperature
- High pH (low H⁺) (less acidic)
- Low CO₂ levels

Unloading of Oxygen

Occurs in tissues when oxygen is released from hemoglobin

Factors that Enhance O₂ Unloading (Release)

- Low PO₂ in tissues
- High CO₂ levels
- Low pH (acidic) (Bohr effect)
- High temperature

Bohr Effect

When increased CO₂ and H⁺ (lower pH) cause hemoglobin to release O₂ more easily

Temperature Effect

Higher temperature = more O₂ release (active tissues); lower temperature = more O₂ binding (lungs)

CO₂ Effect (Haldane Effect)

High oxygen levels promote CO₂ unloading at the lungs; low oxygen promotes CO₂ loading in tissues

Cardiac Cycle

One complete heartbeat — includes contraction (systole) and relaxation (diastole) of the atria and ventricles

1. Atrial Diastole

Atria are relaxed; blood flows into them from veins (vena cavae & pulmonary veins). AV valves open, and ventricles fill passively