CELL BIOLOGY ASSIGNMENT

ASSIGNMENT IN CELL BIOLOGY

Name: April G. Datahan                                        Date: Nov. 25, 2013

Course and year: BSED-III                                   Teacher: Mrs. Rosalinda  V. Pagong

                                   

           

Specialized Cells of the Adult Human Body

Although there are specialized cells - both in structure and function - within the body, all cells have similarities in their structural organization and metabolic needs (such as maintaining energy levels via conversion of carbohydrate to ATP and using genes to create and maintain proteins).

Here are some of the different types of specialized cells within the human body.

Nerve Cells:

·         Also called Neurons, these cells are in the nervous system and function to process and transmit information (it is hypothesized). They are the core components of the brain, spinal cord and peripheral nerves. They use chemical synapses that can evoke electrical signals, called action potentials, to relay signals throughout the body.

Epithelial cells:

·         Functions of epithelial cells include secretion, absorption, protection, transcellular transport, sensation detection, and selective permeability. Epithelium lines both the outside (skin) and the inside cavities and lumen of bodies.

·         Skins cells are square and flat, and provide protection for the internal organs and other vital systems. Being the only barrier between the sensitive inner systems and the outer environment, skin is crucial to protect from infections, chemicals, and other pathogens and pollutive agents.

·         Epithelial cells also serve these functions: insulation, temperature regulation, sensation, synthesis of vitamin D, and protection of Vitamin B folates.

·         Skin is composed of three layers:

·         The epidermis is the outermost layer, forming a waterproof protective wrap for the body.

·         The dermis is the layer underneath the epidermis, and is composed of connective tissue, cushions the body from stress and strain. Mechanoreceptors in this layer provide the sense of touch and heat. This layer also contains the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels, as well as blood vessels.

·         The hypodermis is not part of the skin, and is located below the dermis. The primary function of the hypodermis is to connect the skin to bone and muscle, as well as providing it with nerves and blood vessels.

Exocrine cells:

·         These cells secrete products through ducts, such as mucus, sweat, or digestive enzymes. The products of these cells go directly to the target organ through the ducts. For example, the bile from the gall bladder is carried directly into the duodenum via the bile duct.

Endocrine cells:

·         These cells are similar to exocrine cells, but secrete their products directly into the bloodstream instead of through a duct. Endocrine cells are found throughout the body but are concentrated in hormone-secreting glands such as the pituitary. The products of the endocrine cells go throughout the body in the blood stream but act on specific organs by receptors on the cells of the target organs. For example, the hormone estrogen acts specifically on the uterus and breasts of females because there are estrogen receptors in the cells of these target organs.

Blood Cells: The most common types of blood cells are:

·         red blood cells (erythrocytes). The main function of red blood cells is to collect oxygen in the lungs and deliver it through the blood to the body tissues. Gas exchange is carried out by simple diffusion.

·         various types of white blood cells (leukocytes). They are produced in the bone marrow and help the body to fight infectious disease and foreign objects in the immune system. White cells are found in the circulatory system, lymphatic system, spleen, and other body tissues.

Muscle Cells

·         Muscle cells contain fibers that assist in the contraction and relaxation of muscles. There are three types of muscle cells: skeletal, cardiac, and smooth.

·         Skeletal muscles are connected to bone by tendons, and is used to affect skeletal movement such as posture and locomotion. These muscles are generally consciously controlled.

·         Cardiac muscles are similar to smooth muscle in that it is involuntarily controlled, but they resemble the structure of skeletal muscles. These muscles are only found in the heart.

·         Smooth muscles are located in the walls of most organs, such as the stomach and bladder. These muscles are not able to be consciously controlled.

Adipocyte (Fat) Cells

·         Adipocytes make up adipose tissue, which are efficient at storing fat. There are two types of adipose tissue, known as White Adipose Tissue (WAT), and Brown Adipose Tissue (BAT), which are also known as white and brown fat, respectively.

·         Fat material composed mostly of triglycerides and cholesterol ester is stored in a semi-liquid state inside the white adipose cells. White fat cells also release the hormones resistin, adiponectin, and leptin.

·         Brown fat cells have a polygonal shape, and have considerably more cytoplasm relative to white fat cells. The lipid droplets are scattered throughout the cytoplasm. This brown adipose tissue is also called baby fat, and is used to generate heat.

Gamete (Sex) Cells

·         There are two types of sex cells. Namely, sperm and eggs. Sperm are male sex cells and are composed of a head, midsection, and a tail. The head of a sperm cell contains the nucleus, which holds genetic material and enzymes that are used to penetrate the egg. The midsection has many spiraled mitochondria to produce ATP for the long journey. Lastly, the tail provides the swimming ability by lashing.

·         Female sex cells are called ova, or singularly ovum. The ova of all viviparous animals (including humans), after being fertilized inside the body by a sperm cell, develop as embryos inside the uterus and receives nutrients from the mother.

·         There are technically many more distinct types of cells inside the body, but these are the most fundamental building blocks of our bodies.