Circulatory system Flashcards
Circulatory system (24 cards)
What is an Open Circulatory System?
Blood (hemolymph) is not enclosed in vessels
Examples include insects and mollusks. It has a lower energy requirement but is less efficient in oxygen transport.
What is a Closed Circulatory System?
Blood remains inside vessels
Examples include vertebrates and annelids. It provides more efficient oxygen transport, supporting larger, active animals.
What are the three types of blood vessels in the vertebrate circulatory system?
- Arteries
- Veins
- Capillaries
Arteries carry blood away from the heart, veins carry blood toward the heart, and capillaries are thin-walled vessels for gas and nutrient exchange.
What are the main chambers of the heart?
- Atria
- Ventricles
Atria receive blood, while ventricles pump blood. Valves prevent backflow of blood.
What is Systole in the cardiac cycle?
Contraction phase
It refers to the phase when the heart muscle contracts to pump blood.
What is Diastole in the cardiac cycle?
Relaxation phase
It refers to the phase when the heart muscle relaxes after contraction.
What is Single Circulation?
Blood passes through the heart once per circuit
An example is fish.
What is Double Circulation?
Blood passes through the heart twice per circuit
It includes two separate circuits: pulmonary and systemic.
What is the Pulmonary Circuit?
Heart → Lungs → Heart
It is one of the two circuits in double circulation.
What is the Systemic Circuit?
Heart → Body → Heart
It is the second circuit in double circulation.
What are the main components of blood?
- Plasma
- Red Blood Cells (Erythrocytes)
- White Blood Cells (Leukocytes)
- Platelets
Plasma is the liquid part, erythrocytes carry oxygen, leukocytes provide immune defense, and platelets help in blood clotting.
What is the primary function of Plasma?
Contains nutrients, hormones, and waste
It is the liquid component of blood.
How do gas exchange occur?
Via diffusion across respiratory surfaces
It requires moist surfaces and a high surface area.
What is Countercurrent exchange?
Oxygen flows from water to blood efficiently
This mechanism is seen in gills of fish and amphibians.
What is the Tracheal System?
Air-filled tubes deliver oxygen directly to cells
This system is found in insects.
What are the characteristics of Bird Lungs?
One-way airflow maximizes oxygen uptake
This makes bird lungs more efficient than mammalian lungs.
What is Positive Pressure Breathing?
Air is pushed into the lungs
This mechanism is used by amphibians.
What is Negative Pressure Breathing?
Air is pulled into the lungs by expanding the chest cavity
This is the mechanism used by mammals.
What are Respiratory Pigments?
Bind and transport oxygen
Hemoglobin is the oxygen-carrying protein in red blood cells.
What does the Oxygen Dissociation Curve show?
The relationship between oxygen availability and hemoglobin saturation
It helps understand how hemoglobin releases oxygen.
What is the Bohr Shift?
More oxygen is released at lower pH (when CO₂ levels are high)
This phenomenon helps in oxygen delivery to tissues.
How is CO₂ transported in the blood?
- Dissolved in plasma (~7%)
- Bound to hemoglobin (~23%)
- As bicarbonate ions (HCO₃⁻) (~70%)
These are the three main methods of carbon dioxide transport.
What adaptations do diving mammals have for gas exchange?
- More blood and myoglobin to store oxygen
- Slowed heart rate during dives
- Blood directed to essential organs
Examples include seals and whales.
What adaptations do high-altitude animals have?
More efficient hemoglobin that binds oxygen at low pressures
An example is the Bar-headed Goose.
