Lecture 8A Flashcards
Animal body types that require circulatory systems
More complex multicellular organisms where some cells do not have easy access to the environment for exchange of materials.
Open circulatory system and advantages/disadvantages
Heart; vessels; hemolymph
Not very energy intensive, but does not allow for cell targeting
Closed circulatory system and advantages/disadvantages
Heart; vessels; blood
Allows targeting certain cells with more or less material, but is more energy intensive
Hemolymph v. Blood
Hemolymph: equivalent to interstitial fluid; exists in an open circulatory system
Blood: in closed systems; specialized cells that carry oxygen, as well as interstitial fluid that allows for transport of hormones
Number of heart chambers in fish
Two (AV)
Number of heart chambers in amphibians
three (AVA)
Number of heart chambers in birds
four (AVAV)
Number of heart chambers in mammals
four (AVAV)
Features of single circulatory system
Unoxygenated blood is pumped through the heart to the gill capillaries, where the blood is oxygenated. The blood then goes to body tissues, loses oxygen, and returns to the heart.
Features of double circulatory systems
Have either a pulmocutaneous or pulmonary circuit and a systemic circuit. The blood is oxygenated in the pulmocutaneous/pulmonary circuit, then returns to the heart and is pumped to the systemic system where oxygen is delivered to the body cells.
pulmocutaneous v. pulmonary circuits
Pulmocutaneous: seen in amphibians where exchange happens through the skin; circuit goes to both lung and skin capillaries
Pulmonary: seen in mammals and birds; goes to lung capillaries
Systemic circuits
In double circulatory systems; brings oxygen to the cells in the body
Atrium
Receives blood
Superior portion of heart
Right: unoxygenated blood
Left: oxygenated blood
Ventricle
Sends blood
Inferior portion of heart
Right: unoxygenated blood
Left: oxygenated blood
Valve
Structures that prevent blood from entering a chamber once it has been pumped out.
Artery
Vessels that move away from the heart; pressurized from the heart
Vein
Vessels that move towards the heart; have a valve system that is not pressurized; can flatten
Capillary
Smallest blood vessels that perform the most exchange and exist between arteries and veins
Sinoatrial (SA) node
Valve located in right atrium that is responsible for initiating the heartbeat (pacemaker)
Atrioventricular (AV) node
Valve between atrium and ventricle that prevents blood from re-entering the atrium.
Purkinje fibers
Spread an electrical signal from the apex of the heart to the ventricles; coordinates the constriction of the ventricles. Constriction moves from the apex to the top of the ventricles.
Sinoatrial node cells
aka “pacemaker cells”
Group of cardiac cells known for automatically generating a regular electrical signal. Action potential is specialized to perform an action on a regular basis.
Coordinate atrium constriction
Cellular structures that allow electrical signals (action potentials) to spread directly from one cardiac muscle cell to another
Intercalated discs
Name and describe the three general types of capillaries
Continuous - Standard across the membrane; exchange
Fenestrated - holes; leaky
Sinusoidal - imperfect seals between vessel cells; very leaky
Name the four major components of blood plasma and their functions
Water - Solvent
Ions (electrolytes) - Osmotic balance, pH buffer, regulation of membrane permeability
Plasma proteins - Osmotic balance, pH buffer, defense and immunity, lipid transport, blood clotting
Substances transported by blood - Nutrients, waste products, respiratory gases, and hormones
Three categories of cellular elements found in the blood
Leukocytes (white blood cells), Platelets, and Erythrocytes (red blood cells)