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Root tip, showing young root hairs. Root hairs or absorbent hairs, are outgrowths of epidermal cells, specialized cells at the tip of a plant root.They are lateral extensions of a single cell and are only rarely branched.
Secondary growth thickens the stem and roots, typically making them woody.Obstructions such as this metal post and stubs of limbs can be engulfed. In botany, secondary growth is the growth that results from cell division in the cambia or lateral meristems and that causes the stems and roots to thicken, while primary growth is growth that occurs as a result of cell division at the tips of stems ...
The embryonic heart begins beating at around 22 days after conception (5 weeks after the last normal menstrual period, LMP). It starts to beat at a rate near to the mother's which is about 75–80 beats per minute (bpm). The embryonic heart rate then accelerates and reaches a peak rate of 165–185 bpm early in the early 7th week (early 9th ...
Replacement of a tap root system by a fibrous root is seen in onions, tuberose (Polyanthes tuberosa), grasses, etc. Fibrous roots from normal-stem nodes are seen in grasses like maize, sugarcane, bamboo, etc. Fibrous roots from nodes help in the survival of the plant and thus in vegetative reproduction, when the plant's base is damaged or cut ...
Plant anatomy or phytotomy is the general term for the study of the internal structure of plants.Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
Tricuspid atresia is the complete absence of the tricuspid valve which can lead to an underdeveloped or absent right ventricle. Pulmonary atresia is the complete closure of the pulmonary valve. Ebstein's anomaly is the displacement of the septal leaflet of the tricuspid valve causing a larger atrium and a smaller ventricle than normal.
The normal diameter of the mitral annulus is 2.7 to 3.5 centimetres (1.1 to 1.4 in), and the circumference is 8 to 9 centimetres (3.1 to 3.5 in). Microscopically, there is no evidence of an annular structure anteriorly, where the mitral valve leaflet is contiguous with the posterior aortic root.
In normal anatomy, there is only one conduit for electrical conduction from the upper chambers to the lower chambers, known as the atrioventricular node. The physiologic cardiac skeleton forms a firewall governing autonomic /electrical influence until bordering the bundle of His which further governs autonomic flow to the bundle branches of the ...