GASTRIC GLAND : The  gastric gland  is the basic secretory unit of the stomach and contains a variety of component cells located in char...

LUNGS : The lungs are a pair of spongy, air-filled organs located on either side of the chest (thorax). The trachea (windpipe) conducts i...

Breathing  : Breathing is the process that moves air in and out of the lungs, or oxygen through other respiratory organs such as gills...

Respiratory System : In physiology, respiration is defined as the movement of oxygen from the outside air to the cells within tissues, ...

large intestine : In  mammals , the colon consists of four sections: the  ascending colon , the  transverse colon , the  descending colo...

Small intestine : A thin membrane known as the  mesentery  extends from the posterior body wall of the abdominal cavity to surround the...

HUMAN EXCRETORY SYSTEM : KIDNEYS : The kidneys are bean-shaped organs that serve several essential regulatory roles in vertebrates....

Endocrine glands  : Endocrine glands are glands of the endocrine system that secrete their products, hormones, directly into the blood r...

Circulatory system : The human circulatory system (simplified). Red indicates oxygenated blood carried in arteries, blue indicates deo...

HUMAN PHYSIOLOGY  Human physiology studies how our cells, muscles and organs work together, how they interact. Physiology, sometimes re...