Chat with AIExam 31: Homeostasis: Internal Fluids and Respiration
In some invertebrates,if we cut the nerves leading to the heart and the heart stops beating,the heart is considered
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Discern between a myogenic and a neurogenic heart.What types of organisms possess each?
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Answered by Examlex AI CopilotA myogenic heart is one in which the heartbeat is initiated and regulated by the muscle cells of the heart itself, rather than by external nerves. In a myogenic heart, specialized muscle cells called pacemaker cells generate electrical impulses that spread throughout the heart, causing it to contract and pump blood. These pacemaker cells are located in the sinoatrial (SA) node in mammals, including humans. The myogenic mechanism allows for a more autonomous control of the heartbeat, which can be modulated by the nervous system but is not entirely dependent on it.
Most vertebrates, including mammals, birds, reptiles, and fish, have myogenic hearts. This type of heart is advantageous for these organisms as it allows for more complex regulation of heart rate necessary for their active lifestyles and the varying demands placed on their circulatory systems.
On the other hand, a neurogenic heart is one where the heartbeat is initiated and controlled by the nervous system. In neurogenic hearts, the rhythmic contractions are dependent on regular electrical impulses from the nervous system. Insects and some other arthropods have neurogenic hearts. In these organisms, a series of nerves along the heart release neurotransmitters that trigger the heart muscle to contract. This type of heart allows for a more direct control by the nervous system, which can be beneficial for organisms that do not require as much fine-tuning of heart rate and may have less complex circulatory needs.
In summary, myogenic hearts are found in most vertebrates and are controlled by specialized heart muscle cells, while neurogenic hearts are found in some invertebrates, such as insects, and are controlled directly by the nervous system. Each type of heart is adapted to the specific circulatory requirements of the organisms that possess them.
Which association is NOT correct?
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A dung beetle journeys into a ball of dung to lay eggs.To avoid being poisoned by the noxious gases,it closes its
(87) What are the inherent problems involved in aquatic and aerial breathing?
(71) Opposing the blood hydrostatic pressure that forces water across capillaries is the
(90) Specialized tubules in insects that make direct contact with the tissues to provide oxygen and remove carbon dioxide are called
(73) The pulmonary semilunar valves prevent the backflow of blood into the
(66) Which of the following can NOT serve as a respiratory pigment?
(72) The flap that keeps food and water from going into the larynx is the _______________.
(75) The atrioventricular valves separate the atria from the ventricles in the heart,and the ___________ valves prevent backflow from the pulmonary artery and the aorta.
(85) At sea level,air pressure is 760 mm of mercury (Hg).If we altered the oxygen content in a hospital room to 30% oxygen and 70% nitrogen,the partial pressure of oxygen would be
(74) The major intracellular electrolytes are potassium,magnesium,and phosphate ions,while the chief extracellular electrolytes are sodium,chloride,and ________ _________.
(77) Discuss the physiological mechanism by which the heartbeat is set (e.g.,discuss the pacemaker cells,Purkinje fibers,and the cardiac control center in the brain).
(82) The contraction of the heart is known as ____________,and the relaxation is diastole.
(82) The volume of blood forced from either ventricle each minute is known as _________ _________.
(73) Outline the internal fluid components within a vertebrate organism.
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