The Nervous System, Skeletal Muscle, and Gametogenesis: A Comprehensive Guide

Posted on May 4, 2024 in Biology

The Nervous System

Parasympathetic Nervous System (PSNS)

The Parasympathetic Nervous System is one of the three divisions of the nervous system.

strong> Hormonal cycle facilitates maturation  of the ovarian follicle resulting in the of an ovum (the female reproductive or 11). Each month a series of changes take Which prepares the uterus for pregnancy.  (menstrual cycle) is described below : The first day of menstruation (referred to as Day (1) occurs when levels of estrogen and progesterone are low. In response to these low levels, the hypothalamus secretes gonadotrophin releasing hormone (GnRH) which triggers the anterior pituitary gland to release two hormones: follicle stimulating hormone (FSH), and luteinizing hormone (LH).FSH stimulates the development of many follicles within the ovary. One dominant follicle takes over. As it continues to grow, it produces increasing amounts of estrogen, which stimulates the release of LH, and inhibits FSH, which suppresses further follicular development. When LH levels are highest (LH surge), the ovarian follicle

Gametogenesis

The process by which male and female sex cells or gametes i.e. sperm and oocyte (ovum) are formed respectively in male and female gonads (testes and ovaries) is known as gametogenesis. Thus, gametogenesis in male is known as spermatogenesis and that in female is termed as Oogenesis.

Spermatogenesis

It is the origin and development of sperrn cells within the male reproductive organs, the’ testes. As the individual reaches puberty, the spermatogenesis starts and continues up to old age. The sperm cells are produced within the testes. The testes are composed of numerous tubules known as seminiferous tubules. In the walls of tubules are found numerous spermatogonia (Germinal epithelial cells) situated peripherally and are large cells.

Skin Anatomy

There is another thin layer of translucent cells called stratum lucidum. It generally exists in the tick epidermis. Stratum lucidum represents the ansition phase between stratum granulosum and ratum corneum. Few scientists refer to stratum pinosum and stratum granulosum as the Malpighian layer.

(2) Dermoepidermal Junction/Cutaneous Basement Membrane: This junction represents be acellular zone present between the dermis and he epidermis. The epidermis obtains its nutrition ad also discards its wastes by the process of diffusion at these junctions. As age increases, the rmoepidermal junction gets flattened, which is a ible sign of ageing.
(3) Dermis: Thickness of dermis varies in different parts of the body, for example, on the elids, it is up to 0.6 mm and on the back, palms, and soles it is upto 3 mm. Dermis lies below the pidermis and is made up of a hard, supportive llular matrix.

It consists of the following two layers:

(i) A thin papillary layer, and

(ii) A thicker reticular layer.
(4) Subcutaneous Tissue: It is composed of loose connective tissue and adipose tissue. It is 3cm in thickness on the abdomen. This sheet of adipose tissue is also known as superficial fascia. It contains a layer of areolar tissue having fat and helps in the attachment of the dermis to the underlying structure.