Animal Physiology: The Biological Form Of An Animal

Animal Physiology As the meaning of word ’anatomy’ is the biological form of an animal, physiology means the biological function of an animal. Animal physiology differs in several ways from animal to animal, but all animals share some principal functions. Such functions are attaining nutrients, performing osmoregulation and excretion, and protecting themselves against pathogens. Animals manage these actions by exchanging with the environment. Exchanging is the action when substances in an aqueous solution move across the plasma membrane. Usually this aqueous solution is an interstitial fluid, such as blood. As the animal grows larger, it’s not convenient for them to be single celled as efficiency of exchange depends on the membrane to surface …show more content…
Ingestion and some enzyme activity takes place in the oral cavity. This is a part when digestion is mostly mechanical, but the food activates salivary glands which produce amylase containing saliva. Mucus protects the mouth and makes the food easier to swallow. Tongue helps the bolus, the lump of food, to form and pushes it into the pharynx. The bolus will then travel down through esophagus to the stomach with the help of peristalsis that happens all the way in the esophagus. In the stomach, gastric juice is secreted and mixed with the food to form chyme. Gastric juice consists of HCL and pepsin. HCL creates low pH in the stomach that denatures proteins thus peptide bonds get exposed and vulnerable to pepsin. Proteins are cut up into smaller polypeptides by pepsin. The gastric juice does not destroy the stomach cells because they are activated only when they reach the lumen. HCL composes of hydrogen and chloride ions that are secreted by parietal cells. Pepsin is released by chief cells in the inactive form, pepsinogen. It is the HCL that catalyzes the chain of events of making pepsin …show more content…
The hormonal system is called the endocrine system. It is controlled by the nervous system. There are five major type of methods of molecular intracellular communication. When secreted molecules go into the blood stream and travel throughout the body and affect certain target cells, it is called endocrine signaling. Paracrine signaling affects the neighboring cells. If the target cell is the cell secreting the hormones, it is called autocrine signaling. In synaptic signaling, the target cells response to the neurotransmitters secreted by neurons. Other type of signaling in which neurons take part is neuroendocrine signaling. Neurosecretory cells release hormones from synapses to the circulatory system. The most peculiar part of endocrine signaling is the external chemical signaling. Animals secrete hormones called pheromones to signal other members of its population or even other