DEFINE GUTTATION.

Secretion of water on to the surface of leaves through specialized pores, or hydathodes. The process occurs most frequently during conditions of high humidity when the rate of transpiration is low. Drops of water found on grass in early morning are often the result of guttation, rather than dew

DEFINE homeostasis,osmoregulation,thermoregulation and excretion.

1. Homeostasis;

is the property of a system, either open or closed, that regulates its internal environment and tends to maintain a stable, constant condition.

2.osmoregulaion;

Osmoregulation is the control of the levels of water and mineral salts in the blood. It is a homeostatic mechanism.

3.EXCRETION;

Excretion is the process of eliminating waste products of metabolism and other non-useful materials. It is an essential process in all forms of life.

How heat is gained by human body?

The body gains heat by radiation, by convection, by conduction, and as a by-product of physiological processes that take place within the body.

the heat gain by radiation comes from our surroundings. However, heat always travels from areas of higher temperature to areas of lower temperature.

Deffrentiatebetween hydrophyte,halophytes,mesophytes,xerophytes.

1. hydrophytes;

A hydrophyte is a plant that grows in water or in water-logged soil, with submerged  storage organs and perennating bud (s) resting below the water level.

Hydrophytes have a reduced root system, reduced support and vascular systems, and specialized leaves.

2.Halophytes;

Halophytes are plants which tolerate or even demand sodium chloride concentrations in the soil water they absorb. Depending on the habitat conditions they have developed different strategies to survive in sometimes very high salt content in the soil water.

3.mesophytes;

Mesophytes are terrestrial plants which are adapted to neither a particularly dry nor particularly wet environment.

4.xerophytes;

Some plants are called xerophytes, which means they are able to with stand long dry periods of high temperature by conserving what little water there is available. These plants are commonly known as succulents, as they are able to store water in their tissues.

What is vasoconstriction and vasodilation?

1.Vasoconstriction;the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of

vasodilation, the widening o

2.vasodilation;Vasodilation refers to the widening of blood vessels [1] resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins.

The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels.

6. Define radiation, convection and evaporation. 1, Radiation;radiation describes a process in which energetic particles or waves travel through a medium or space. There are two distinct types of radiation, ionizing and non-ionizing.

2, convection;Convection is the movement of molecules within fluids (i.e. liquids, gases and rheids). It cannot take place in solids, Convection is one of the major modes of heat transfer and mass transfer.

3,Evaporation;Evaporation is the process by which water is converted from its liquid form to its vapor form.

Differentiate between(a)homeotherms and poikilotherms

(b)ectothermic animals and endothermic animals

(b) homoiotherms and poikilotherms; (i) An organism that maintains its body temperature at a constant level, usually

above that of the environment, by its metabolic activity.they are also called

warm blooded animals.

(ii) poikilotherm is a plant or animal whose internal temperature varies along with that of the ambient environmental temperature.

(b)ectothermic animals and endothermic animals

(I) ectothermic animals;

Cold-blooded animals (ectotherms) are animals that do not have an internal mechanism for regulating body temperature, relying instead on solar energy captured by the environment. Reptiles, amphibians and fish are examples of cold-blooded animals.

(II) endothermic animals;

a warm-blooded (or homeothermic) animal species is one whose members maintain thermal homeostasis; that is, they keep their body temperature at a roughly constant level, regardless of the

ambient temperature.

Structure and function of kidnoys

the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine. A nephron eliminates wastes from the body, regulates blood volume and blood pressure, controls levels of electrolytes and metabolites, and regulates blood pH. Its functions are vital to life and are regulated by the endocrine system by hormones such as antidiuretic hormone,

aldosterone, and parathyroid hormone.[1] In humans, a normal kidney contains 800,000 to one million nephrons.[2]. Each nephron is made of intricately interwoven capillaries and drainage canals to filter wastes, macromolecules, and ions from the blood to urine. The approximately 1 million nephrons in each human kidney form 10-20 cone-shaped tissue units called renal pyramids that span both the inner and outer portions of the kidney, the renal medulla and renal cortex.

Renal Corpuscle Structure;

he renal corpuscle is the initial filtering component of the nephron and is made up of two structures known as the glomerulus and Bowman’s capsule. The Bowman’s capsule is a double membrane that cups the glomerulus. The glomerulus is a capillary extension, a small network of thin blood vessels, receiving blood from the renal circulation. The glomerular filtration rate is a measure of kidney function.

Renal Tubule Structure;

Renal tubules are a duct system beginning at the Bowmen’s capsule in the cortex, looping through the renal medulla, and returning to the cortex to connect to the collecting duct system. Each renal tubule is divided into a proximal tubule, loop of Henle, and distal convoluted tubule. The proximal tubular has a brush border, that is microvilli, that increases the surface area for absorption.

proximal tubule; The proximal tubule is the portion of the duct system of the nephron of the kidney which leads from Bowman's capsule to the loop of Henle. The most distinctive characteristic of the proximal tubule is its brush border.

loop of Henle; In the kidney, the loop of Henle (or Henle's loop or ansa nephroni) is the portion of the nephron that leads from the proximal straight tubule to the distal convoluted tubule. The main function of this structure is to create a concentration gradient in the medulla of the kidney.

distal convoluted tubule; The distal convoluted tubule (DCT) is a portion of kidney nephron between the loop of Henle and the collecting duct system. It is partly responsible for the regulation of potassium, sodium, calcium, and pH

The Functions of the Nephron ;The nephron is component of the homeostatic mechanism of your body. A nephron is the fundamental structural and functional part of the kidney. Its principal function is to control the absorption of water and soluble substances such as sodium salts by filtering the blood, reabsorbing what is required and excreting the rest as urine. A nephron gets rid of wastes from the body, controls blood volume and pressure, regulates levels of electrolytes and metabolites, and regulates blood pH. Its functions are very important to life and are controlled by the endocrine system by hormones.