Canine Cardiovascular and Respiratory Systems, Vital Signs, and Clinical Examination

Comprehensive vocabulary flashcards covering canine vital signs, clinical physical exams, respiratory and cardiovascular anatomy, physiology, and common emergency ailments.

Normal Canine Body Temperature

The normal internal body temperature of a dog measured rectally, which ranges between $100.0^\circ\text{F}$ and $102.5^\circ\text{F}$ ($38.3\text{--}39.2^\circ\text{C}$); values under $99.0^\circ\text{F}$ or over $104.0^\circ\text{F}$ ($37.2\text{--}40.0^\circ\text{C}$) indicate immediate veterinary concern.

Canine Fever

An abnormal elevation of rectal body temperature exceeding $103.0^\circ\text{F}$, where the standard canine baseline range is $101.0^\circ\text{F}\text{ to }102.5^\circ\text{F}$.

Canine Heart Rate

The frequency of heartbeats measured in beats per minute (BPM) using a stethoscope or palpation (chest or femoral artery), calculated as beats in $15\text{ seconds} \times 4$, with a normal resting range of $40\text{--}120\text{ BPM}$ and a typical healthy normal of $60\text{--}100\text{ BPM}$.

Canine Respiratory Rate

The frequency of breathing cycles measured in respirations per minute (RPM) by observing chest movement or auscultating with a stethoscope, calculated as breaths in $15\text{ seconds} \times 4$, with a general range of $10\text{--}30\text{ RPM}$ and a resting normal of $18\text{--}24\text{ RPM}$.

Capillary Refill Time (CRT)

A clinical assessment of peripheral perfusion determined by pressing the gums until blanched and measuring the time needed for color to return; normal is $1\text{--}2\text{ seconds}$, exceeding $2\text{ seconds}$ indicates potential dehydration or shock, and exceeding $4\text{ seconds}$ is a medical emergency.

Pale or Light Pink Mucous Membranes

An abnormal gum discoloration indicating shock, anemia, clotting disorders, heart problems, hypothermia, or internal bleeding.

Bright Cherry Red Mucous Membranes

An abnormal gum coloration indicating heatstroke, exposure to toxins, high blood pressure, or carbon monoxide poisoning.

Cyanosis (Blue / Purple Mucous Membranes)

An abnormal bluish or purplish discoloration of mucous membranes indicating lack of oxygen, respiratory distress, pneumonia, asthma, choking, low blood pressure, or hypothermia.

Icterus (Yellow Mucous Membranes)

A yellowish discoloration of the mucous membranes and tissues caused by elevated bilirubin, indicating liver problems or jaundice.

Asphyxiation

A condition in which the air supply to the body is blocked from entering, which can rapidly result in death if left unchecked.

Canine Choking

An acute obstruction of the airway preventing respiration, caused by foreign items (food, chews, toys) or allergic swelling of the throat; characterized by gagging sounds, bulging eyes, pawing at the mouth, and cyanotic lips.

Abdominal Thrusts (Canine)

An emergency physical procedure used on a larger choking dog to force air out of the lungs and expel an airway obstruction by placing hands in the natural hollow below the ribs and pushing inward and upward.

Anaphylactic Shock

A severe, potentially fatal systemic hypersensitivity reaction developing within $1\text{--}30\text{ minutes}$ of contact with a foreign allergen (e.g., stings, drugs, food, chemicals), requiring emergency shock therapy and an epinephrine injection.

Coughing

A protective reflex action triggered by irritation anywhere along the respiratory tract, precipitated by excitement, leash pulling, infectious tracheobronchitis (kennel cough), pneumonia, heartworm, or congestive heart failure.

Body Condition Score (BCS)

A standardized clinical evaluation metric ranging from 1 (emaciated) to 9 (grossly overfat) that estimates body fat percentage based on palpable rib coverage, waistline visibility, and abdominal tuck; adult dogs with BCS $< 5$ live $16\%$ longer than overweight peers.

Upper Respiratory Tract

The anatomical division of the respiratory system located outside the thorax, consisting of the nostrils, nasal passages, pharynx, larynx, and trachea.

Lower Respiratory Tract

The internal pulmonary airway structures within the thoracic cavity, consisting of the bronchi, bronchioles, alveolar ducts, and alveoli.

Phonation

The process of voice production originating in the larynx, where bilateral vocal cords (vocal folds) stretch across the laryngeal lumen and vibrate as air passes over them.

Respiratory Thermoregulation

The physiological cooling and temperature stabilization mechanism in dogs achieved by circulating air across extensive networks of superficial blood vessels lining the nasal passages and through panting.

Nasal Turbinates

Fine, scroll-like bones within the nasal cavity lined by pseudostratified ciliated columnar epithelium, mucus, and blood vessels that warm, humidify, and trap debris from incoming air.

Pharynx

The muscular throat corridor that serves as a common passageway for both the respiratory and digestive systems.

Larynx

The cartilaginous 'voice box' connecting the pharynx to the trachea that protects the lower airway, controls airflow, and houses the vocal folds.

Trachea

A short, wide tubular windpipe composed of fibrous tissue and smooth muscle held permanently open by cartilaginous rings, channeling air from the larynx to the bronchi.

Alveoli

Microscopic, thin-walled sac-like structures clustered into alveolar sacs at the ends of alveolar ducts where vital gas exchange between air and capillary blood occurs.

Diaphragm

A thin sheet of skeletal muscle forming the caudal anatomical boundary of the thorax that acts as the primary muscle of respiration.

Inspiration

The active ventilatory process of drawing air into the lungs resulting from an expansion in thoracic volume, causing the lungs to expand passively.

Expiration

The ventilatory process of pushing air out through the respiratory passageways as the thorax decreases in volume and compresses the lungs.

Cardiovascular System

The body system comprising the heart and blood vessels that continuously circulates blood to deliver oxygen and nutrients to tissues and remove metabolic waste products.

Base of the Heart

The rounded, broad cranial aspect of the heart where the atria are located and the major blood vessels enter and exit.

Apex of the Heart

The pointed caudal extremity of the heart formed by the ventricles, oriented ventrally and tilted toward the left side within the thoracic cavity.

Pericardium

The fibroserous outer protective covering of the heart, consisting of an outer fibrous pericardium, an inner two-layered serous pericardium (parietal and visceral layers), and a fluid-filled pericardial space.

Atria

The two cranially positioned receiving chambers of the heart (singular: atrium) that form the cardiac base and are separated by the interatrial septum.

Ventricles

The two muscular, caudally positioned pumping chambers of the heart that form the apex, separated by the interventricular septum, responsible for propelling blood into the pulmonary and systemic circulations.

Cardiac Valves

Four internal one-way fibrous structures (pulmonary semilunar, aortic semilunar, tricuspid, and mitral valves) that regulate unidirectional blood flow through the heart chambers.

Chordae Tendineae

Tendinous cord-like structures connecting the margins of the atrioventricular valves to papillary muscles, preventing the valve flaps from prolapsing backwards into the atria during ventricular contraction.

First Heart Sound ("Lub")

The initial distinct sound of a cardiac cycle produced by the simultaneous snap closure of the tricuspid and mitral (atrioventricular) valves during ventricular systole.

Second Heart Sound ("Dub")

The second distinct sound of a cardiac cycle produced by the snap closure of the pulmonary and aortic (semilunar) valves at the termination of ventricular systole.

Arteries vs. Veins

Arteries carry pressurized blood away from the heart with a thick smooth muscle and elastic tunica media, whereas veins carry low-pressure blood toward the heart, contain one-way valves, and have a thicker outer connective tissue layer.

Capillaries

Microscopic, thin-walled vessels organized into capillary beds where blood vessel walls are only one endothelial cell thick to facilitate rapid nutrient and gas diffusion.

Venipuncture Sites (Canine)

Superficial veins accessed for blood sample collection, intravenous fluid or medication administration, and catheter placement, including the jugular vein (neck), cephalic vein (cranial forelimb), and lateral saphenous vein (lateral pelvic limb).