| Diffusion | Happens where there is a difference in concentration; can also result to net movement of particles |
| Square of the distance | The time it takes to diffuse from one place to another is proportional to the |
| Circulatory system | Alternative adaptation for efficient exchange of animals that lack a simple body plan |
| Gastrovascular Cavity | Functions in the distribution of substances throughout the body as well as in digestion for animals such as hydra, jellies, and other cnidarians |
| Increasing surface area and minimizing diffusion distances | A flat body optimizes exchange by |
| circulatory fluid, interconnecting vessels, and muscular pump (heart) | Three basic components of a circulatory system |
| open or closed | Circulatory systems are either |
| Hemolymph | Interstitial fluid in a closed circulatory system that bathes body cells |
| Blood | Circulatory fluid in closed circulatory system that is confined to vessels and is distinct from interstitial fluid |
| Uses less energy | Open circulatory system benefits |
| Effective delivery of oxygen and nutrients | Closed circulatory system benefits |
| Cardiovasular system | Term used to describe the heart and blood vessels in vertebrates |
| Arteries, Veins, Capillaries | Three main types of blood vessels |
| Arterioles | Convey blood to capillaries |
| Capillaries | Microscopic vessels with very thin, porous walls |
| Capillary beds | Network of capillaries |
| away | Arteries carry blood _____ the heart |
| toward | Veins carry blood ______ the heart |
| atria/atrium | The chamber that receives blood entering the heart |
| ventricle | Chamber/s responsible for pumping blood |
| Single Circulation | Blood travels through the body and returns to its starting point in a single circuit or loop |
| Double Circulation | Have two circuits of blood flow |
| Pulmonary Circuit | Gas exchange takes place in the lungs |
| Pulmocutaneous Circuit | Gas exchange takes place in capillaries in both the lungs and skin |
| Systemic Circuit | Begins with the left side of the heart pumping oxygen-enriched blood from the gas exchange tissues to capillary beds in organs and tissues throughout the body |
| oxygen-poor blood | The right side of the heart receives |
| oxygen-rich blood | The left side of the heart receives |
| Cardiac Muscle | The human heart consists mostly of |
| it pumps blood | When the heart contracts |
| it fills its chambers with blood | When the heat relaxes |
| Cardiac Cycle | One complete sequence of pumping and filling |
| Systole | Contraction phase of the cycle |
| Diastole | Relaxation phase of the cycle |
| Cardiac Output | Volume of blood each ventricle pumps per minute |
| Heart rate | Rate of contraction of the heart; number of beats per minute |
| Stroke Volume | Amount of blood pumped by a ventricle in a single contraction |
| Valves | Prevent backflow and keep blood moving in the correct direction |
| Atrioventricular Valve | Lies between each atrium and ventricle ; anchored by strong fibers that prevent them from turning inside out during ventricular systole |
| Semilunar Valve | Located at the two exits of the heart where the pulmonary artery leaves the right ventricle and where the aorta leaves the left ventricle |
| AV valve | Lub sound is created by the |
| SL valve | Dub sound is created by the |
| Heart murmur | Abnormal sound produced when blood squirts through a defective valve |
| Sinoatrial Node (pacemaker) | Sets the rate and timing at which all cardiac muscle cells contract via the production of electrical impulse much like those produced by nerve cells |
| Electrocardiodiagram (ECG/EKG) | Measures the electrical activity of the heart |
| Atrioventricular node | Relay point where impulses are delayed by 0.1 second before spreading to the heart apex |
| Bundle branches and Purkinje Fibers | Specialized structures that relay the electrical signals from the heart apex |
| Speeds up | Sympathetic division in the body trigger physiological cues that ____ the heart tempo |
| Slows down | Parasympathetic division in the body trigger physiological cues that ______ the heart tempo |
| Body temperature | Type of input that also affects the pacemaker; evident when you have a fever |
| Endothelium | Single layer of flattened epithelial cells |
| Capillaries | Smallest blood vessels |
| Basal Lamina | Capillaries consists of a surrounding extra layer called |
| two | How many layers does arteries and veins have in their walls |
| Connective Tissues | The outer layer of arteries and veins is formed by |
| Smooth Muscle | Layer next to endothelium of arteries and veins |
| valves | Veins contain _____ that prevent backflow |
| Slow down; larger | Blood pressure in capillaries ______ due to ____ cross sectional area compared to veins and arteries |
| Ventricular systole | Arterial blood pressure is highest when the heart contracts during |
| Systolic pressure | Pressure during pumping of blood |
| Pulse | Rhythmic bulging of the artery walls with each heartbeat |
| Diastolic Pressure | Pressure when ventricles are relaxed |
| Vasoconstriction | Process when the smooth muscles in arteriole walls contract and the arterioles narrow |
| Vasodilation | A process that tends to increase the diameter that causes blood pressure in the arteries to fall |
| Nitric Oxide | Gas as an inducer of vasodilation |
| Endothelin | Peptide that is the most potent inducer of vasoconstriction |
| Sphincters | Rings of smooth muscle at the entrance to capillary beds |
| Dissolved proteins | Responsible for much of the blood's osmotic pressure |
| Lymphatic System | System that recovers and returns the lost fluid and proteins |
| Lymph | Recovered fluid; circulates within the lymphatic system before draining into a pair of large veins of the cardiovascular system at the base of the neck |
| Lymph Vessels | Like veins, have valves that prevent the backflow of fluid |
| Edema | Fluid Accumulation in affected tissues |
| Elephantiasis | Condition marked by extreme swelling in limbs or other parts of the body |
| Lymph Nodes | Small lymph filtering organs; play an important role in the body's defense |
