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The medulla is the innermost layer of the hair shaft. This nearly invisible layer is the most soft and fragile, and serves as the pith or marrow of the hair. Some mammals don't have a medulla in their hair. The presence or absence of this layer and the characteristics of the medulla can aid taxonomists in identifying what taxa a hair comes from.
Diagram of the hair shaft, indicating medulla (innermost), cortex, and cuticle (exterior.) Anatomy of hair. The cortex of the hair shaft is located between the hair cuticle and medulla and is the thickest hair layer. It contains most of the hair's pigment, giving the hair its color. The major pigment in the cortex is melanin, which is also ...
Embryonic vertebrate subdivisions of the developing human brain hindbrain or rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates. It includes the medulla, pons, and cerebellum.
In mammalian outer hair cells, the varying receptor potential is converted to active vibrations of the cell body. This mechanical response to electrical signals is termed somatic electromotility; [13] it drives variations in the cell's length, synchronized to the incoming sound signal, and provides mechanical amplification by feedback to the traveling wave.
Hair exists in a variety of textures. Three main aspects of hair texture are the curl pattern, volume, and consistency. All mammalian hair is composed of keratin, so the make-up of hair follicles is not the source of varying hair patterns. There are a range of theories pertaining to the curl patterns of hair.
The ways in which the human brain differs from other brains are covered in the human brain article. Several topics that might be covered here are instead covered there because much more can be said about them in a human context. The most important that are covered in the human brain article are brain disease and the effects of brain damage.
The hair follicle is an organ found in mammalian skin. [1] It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions.. The hair follicle regulates hair growth via a complex interaction between hormones, neuropeptides, and immune cells
The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. [1] It is anterior and partially inferior to the cerebellum . It is a cone-shaped neuronal mass responsible for autonomic (involuntary) functions, ranging from vomiting to sneezing . [ 2 ]