Homeostasis or Osmoregulation, Homeostatic Process and the Parts Involved in Homeostatis

Homeostasis is defined as the maintenance of a fairly constant internal environment in an organism. All living organisms must be able to maintain a steady environment. Body fluid such as blood, lymph and tissue fluids make up the internal environment of the organism. 

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Care of the Skin

There is need to properly take care of the skin. If the sweat and oily substances are not removed from the body on time, dust and bacteria will stick to the surface of the skin. 

Dirty skin promotes bacteria and other pathogenic growth as well as blockage of the sweat pores. Some skin diseases can even develop as well as unpleasant body odour. All these may prevent the skin from performing its normal functions. 

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Functions of the Skin

The important functions of the skin include:

1. Protection: The skin protects the body against entrance by microbes, mechanical injuries, ultra-violet rays of the sunlight and desiccation by acting as waterproof. The pigment, melani absorbs ultra-violet rays from the sun which is harmful to the body.

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The Skin and Its Structure

The skin is the outer covering of vertebrates. It forms a continuous layer over the entire body, making it the largest organ. In mammals, the skin usually bears a dense growth of hairs. Human beings, however, only have a sparse growth of hair over most parts of their bodies.

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Diseases of the Liver, their Effects and Remedies

Certain diseases can impair the functioning of the liver. 

They include:

1. Diabetes mellitus: This disease is caused as a result of the inability of the liver cells to convert excess glucose in the blood to glycogen. This is as a result of the failure of the pancreas to produce a hormone called insulin. Consequently, excess sugar is left in the blood and lost through urine.

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The Liver and Its Functions

The liver is a large reddish-brown organ with two lobes. It lies just below the diaphragm to the right side, partly overlapping the stomach. Its average weight is about 1.25kg. Each lobe of the liver is subdivided into smaller lobes 


[image credit: Bruce]

The gall bladder which stores the bile is connected to the duodenum by a short tube called bile duct. The bile duct is a soft organ with a rich and extensive blood supply.

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Diseases of the Kidneys, their Effects and Remedies

DISEASES OF THE KIDNEYS



1. Diuresis: This is a condition in which the cells of the kidney tubules are not reabsorbing water from the glomerular filtrate, and as a result, a large amount of water is  passed out in urine. Diuresis can also occur from a patient, suffering from diabetes insipidus - a condition in which the production of ADH (Anti-Diuretic Hormone) becomes reduced. Less water is reabsorbed and the patient produces a lot of urine - about 5-20 litres a day.

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Functions of The Kidneys and Conditions Affecting Them

The structure of the kidneys has already been discussed here.

FUNCTIONS OF THE KIDNEYS


[photo credit: Michal]

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Dental Formula, Adaptation of Mammalian Teeth for Feeding and Dental Care

DENTAL FORMULA

[Photo credit: Dozenist]

Dental formula can be defined as the number and types of teeth an animal has in one half of each jaw. Different mammals have different dental formulae depending on their diet. In the following formulae:

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Feeding, Digestion and Dentition in Mammals

The solid food most animals eat is usually large, and must first be broken down into small molecules in the alimentary canal before it can be absorbed in the blood stream. This is usually done mechanically and chemically in mammals. 

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Feeding Mechanism and Modifications in Some Animals

There are five modifications and mechanisms of feeding associated with some organisms. These feeding mechanisms include:

1. Biting and chewing mechanism e.g. grasshopper or cockroach: The grasshopper or cockroach has mouth parts adapted for biting and chewing. 

[Photo credit: Fir0002. License: GFDL. Released under GFDL v1.2]

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Digestive System of Rabbit and Other Herbivores

DIGESTIVE SYSTEM OF RABBIT


[Photo credit: Larry D. Moore. License: CC-BY-SA 3.0]

The teeth of herbivores are adapted for cropping grass and grinding plant matter to break down the cellulose cell walls. The incisors of a rabbit are long and chisel-shaped. They bite against each other to chop off pieces of grass.

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Digestive System or Alimentary Canal of Man

The alimentary canal is a long tube stretching from the mouth to the anus. The digestive system or alimentary canal of man includes: the mouth, oesophagus, stomach, duodenum, small intestine or ileum, caecum, appendix, large intestine or colon, rectum and anus. 

[Photo credit: Bruce Blaus]

The description and importance of the parts are as follows:

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Digestive System of Planaria, Tapeworm, Amoeba, Earthworm, Insects and Bird

DIGESTIVE SYSTEM OF PLANARIA

[Photo credit: PlanMine]

The planaria is a free-living flatworm that feeds on aquatic animals called zooplanktons. It has a simple alimentary canal with one opening - the mouth. The mouth opens into a short buccal cavity which leads into the pharynx.

The pumping action of the pharynx sucks in pieces of food which enter the pharynx and pass into the small intestine. The small intestine has three branches - one leading to the head and the other two towards the tail. The branches give off numerous side branches.

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Digestion, Digestive System and Feeding Mechanism

Digestive System includes the alimentary tract or canal and all the organs and glands associated with the digestion and assimilation of food in animals.The digestive system varies from one animal to another, Organisms from simple to complex ones have different types of digestive systems or alimentary tract.


Animals have different types of alimentary tracts which vary in size, complexity, mode of feeding or type of diet. However, there is no definite alimentary canal in plants.

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Excretory System of Plants

Plants have no special excretory organs because their metabolic waste products are minimal. Plants manufacture their own food, i.e they are autotraphic. The waste materials are disposed off through various parts of the plant. 

[Photo credit: Estreya]

Plant wastes products include water, carbon dioxide oxygen, acids, resins, mucilage, latex, alkaloids, crystals of salts, oils, gum and anthocyanin.

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EXCRETORY SYSTEM OF MAMMALS: Structure and Mechanism of Excretion of the Kidney and Urinary Tubule

EXCRETION IN MAMMALS

[Photo credit: Jordi March i Nogué]

In mammals, there are four excretory organs:

• lungs, which excrete water vapor and carbon dioxide;
• skin, which excretes water, salts and urea through sweat;
• liver, which excretes bile pigments called bilirubin; and
• kidneys, which excrete water, mineral salts, urea, uric acid, and creaunine.

EXCRETORY SYSTEM OF MAMMALS

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Excretory System and Mechanism of Excretion in Earthworm, Flatworm, Insects and Amoeba

EXCRETORY SYSTEM OF EARTHWORM

[Photo credit: KDS444. Earthworm_head.svg from wikipedia commons. License: CC-BY-SA 3.0]

An earthworm has a segmented body. Each segment of the body except the first three and the last segment has a pair of tubes called nephridia. The nephridia are the excretory organs of the earthworm.

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EXCRETION: Definition, Importance, Need for Excretory Systems, Organisms and Their Excretory Organs, Excretory Organs and Their Waste Product

Excretion can be defined as the process by which metabolic waste products are removed from the body of living things. Waste product from metabolic activities are always produced by the bod and their removal are carried out by special excretory systems or organs. 


[Photo credit:  Hämbörger. License: GNU Free Documentation License]

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Respiratory System in Plants

Plants carry out gaseous exchange for: photosynthesis and cellular respiration.


[Photo credit: Yvan Lindekens]

Photosynthesis is the process by which green plants manufacture their food, making use of carbon dioxide and water in the presence of sunlight.

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