Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Atrio-ventricular Orifices
The right and left atrio-ventricular orifices are oval apertures. The openings lie in a plane that is almost vertical with a slight downward inclination. Each opening is directed forwards then left and slightly downwards. Each orifice is strengthened by a variable amount of fibrous tissue around it. It is guarded by a valve which allows flow of blood, only from atrium to ventricle but not in the reverse direction. The valves are made up of cusps which are thin leaflets of tissue. Each cusp consists of a double fold of endocardium within which is some fibrous tissue. It has two surfaces, ventricular and atrial. It has a base which is attached to the ring of fibrous tissue around the Atrio-ventricular orifice. It has an apex and free margins. The margins of adjoining cusps are fused to each other for some distance so that the cups form a continuous membrane. The apex and the margins give attachment to tendinous strands called the chordae tendinae. The chordae tendinae are also attached to the ventricular surfaces of the cusps which are therefore, rough in contrast to the atrial surface which are smooth. At their other end the chordae tendinae are attached to the apices of the papillary muscles. Each papillary muscle through the chordae tendinae is attached to the adjoining part of the two cusps. As a result the adjoining margins of the two cusps are drawn together when the papillary muscle contracts.
The features peculiar to each orifice are: the right orifice is larger than the left; it admits the tips of three fingers. In contrast the left orifice is smaller and admits the tips of two fingers. The arrangements of cusps and papillary muscles also differ.
Nutrition As we have said earlier all animals are heterotrophs and require food from the environment. What is this food made up of? If the food of a number of different animal
Summer Stratification - Thermal stratification Thermal stratification is fairly pronounced during the summer seasons in most lakes of the temperate (cold) regions but is rare
P o lymerase chain reaction (PCR): The PCR technique enables the exponential amplification of nucleic acid sequences from any biological samples. In the last few ye
What are the female pronucleus and the male pronucleus? The female pronucleus is the proper haploid nucleus of the egg cell. Male pronucleus is the haploid nucleus of the sperm
What are the two models that explain Mechanism of Hormone Action on their target?
Red-green colour blindness is X-linked recessive. A woman with normal colour vision has a father who is red-green colour-blind. The woman has four sons, none of whom are colour-bli
Dicots are one of the two main types of flowering plants; characterized by having two cotyledons, floral organs arranged in the cycles of four or five, and leaves with the reticul
Define Treatment and Management of Adverse Food Reactions? Management of adverse food reactions involves diagnosing the problem followed by nutritional and medical care.
Ecosystem as a Unit of Nature An ecosystem can be visualised as a functional unit of nature representing complex interactions between living and non-living components. Th
Q What are the three major types of nitrogen wastes excreted by living beings? The main nitrogen wastes excreted by living beings are ammonia, urea and uric acid. Living beings
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +1-415-670-9521
Phone: +1-415-670-9521
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd