what is the function of a hair follicle
Hair follicle The hair follicle is a dynamic 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.[1] This complex interaction induces the hair follicle to produce different types of hair as seen on different parts of the body. For example, terminal hairs grow on the scalp and lanugo hairs are seen covering the bodies of fetuses in utero and in some new born babies.[1] The process of hair growth occurs in distinct sequential stages. The first stage is called anagen and is the active growth phase, catagen is the resting stage, telogen is the regression of the hair follicle phase, exogen is the active shedding of hair phase and lastly kenogen is the phase between the empty hair follicle and the growth of new hair.[1]
Ovulation The process of ovulation is controlled by the hypothalamus of the brain and through the release of hormones secreted in the anterior lobe of the pituitary gland, luteinizing hormone (LH) and follicle-stimulating hormone (FSH).[8] In the preovulatory phase of the menstrual cycle, the ovarian follicle will undergo a series of transformations called cumulus expansion, which is stimulated by FSH. After this is done, a hole called the stigma will form in the follicle, and the secondary oocyte will leave the follicle through this hole. Ovulation is triggered by a spike in the amount of FSH and LH released from the pituitary gland. During the luteal (post-ovulatory) phase, the secondary oocyte will travel through the fallopian tubes toward the uterus. If fertilized by a sperm, the fertilized secondary oocyte or ovum may implant there 6â€“12 days later.[9]