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A pistil typically consists of an expanded basal portion called an ovary, an elongated section called a style and an apical structure called a stigma that receives pollen. The ovary (from Latin ovum , meaning egg) is the enlarged basal portion which contains placentas , ridges of tissue bearing one or more ovules (integumented megasporangia ).
The stigma, together with the style and ovary (typically called the stigma-style-ovary system) comprises the pistil, which is part of the gynoecium or female reproductive organ of a plant. The stigma itself forms the distal portion of the style, or stylodia, and is composed of stigmatic papillae , the cells of which are receptive to pollen.
Parachute mitral valve occurs when all the chordae tendineae of the mitral valve attach to a single papillary muscle. [9] [10] [11] This causes mitral valve stenosis at an early age. [10] It is a rare congenital heart defect. [11] Although it often causes mitral insufficiency, it may not present any symptoms. [10]
The floral axis serves as the attachment point for organs of the flower, such as the reproductive organs (pistil and stamen) and other organs such as the sepals and carpels. [6] The floral axis acts much like a modified stem and births the organs that are attached to it. [ 7 ]
The column, or technically the gynostemium, is a reproductive structure that can be found in several plant families: Aristolochiaceae, Orchidaceae, and Stylidiaceae. It is derived from the fusion of both male and female parts ( stamens and pistil ) into a single organ. [ 1 ]
More severe symptoms are reflex bradycardia, which is a reduction in the blood pressure due to the decrease in cardiac output via an increase in heart rate, negative inotropic effects on the heart muscle, which weakens the force of muscle contractions, and In high doses, the narrowing of skin and skeletal muscle blood vessels.
Cardiac muscle Cardiac sarcomere structure . Cardiac muscle tissue or myocardium forms the bulk of the heart. The heart wall is a three-layered structure with a thick layer of myocardium sandwiched between the inner endocardium and the outer epicardium (also known as the visceral pericardium).
T-tubules (transverse tubules) are extensions of the cell membrane that penetrate into the center of skeletal and cardiac muscle cells.With membranes that contain large concentrations of ion channels, transporters, and pumps, T-tubules permit rapid transmission of the action potential into the cell, and also play an important role in regulating cellular calcium concentration.