Welcome to Zoology World

balindrakumar033@gmail.com   19/01/2018,Friday

WELCOME TO ZOOLOGY WORLD

The science or study of animal life. Together with botany, the study of plant life, it forms the science of biology. Zoology is such a vast subject that most zoologists specialize or focus on the study of particular organisms or taxonomic groups. tion of animals.

(ii)Neurosensory epithelium:

Olfactory mucos,called Schneiderian membrane,lining of internal nares,retina of eyes

Olfactory mucosa,called Schneiderian membrane,lining of internal nares,retina of eyes and epithelial covering of tongue containing taste buds are examples of neurosensory epithelia.The sensory cells bear,at their free ends,slender"sensory hairs" to receive specific stimuli.Basely,these cells are connected,by means of synapses, with fine fibrils of sensory nerves.

(iii)Pigmented epithelium:

The epithelial cells of the basal layer of retina contain pigment.Hence,this layer
is often referred to as a pigmented epithelium.e.g.,Pigmented layer of retina,

The epithelial cells of the basal layer of retina contain pigment.Hence,this layer is often referred to as a pigmented epithelium.e.g.,Pigmented layer of retina, iris and skin.

(iv)Germinal epithelium:

Germinal epithelium produces gametes e.g.,Ova(Female gametes)and Sperm
(Male gametes).

Specialized cuboidal cells capable of producing gametes as found in gonads. Germinal epithelium produces gametes e.g.,Ova(Female gametes)and Sperm (Male gametes).

What is gland

A cell,tissue or organ which
secretes a useful chemical material is known as gland

Glandular epithelium are specialized for secretory activity.A cell,tissue or organ which secretes a useful chemical material is known as gland.Glands are made up of cuboidal epithelial cells which are more secretory.All glands arise as folding of epithelia. The golgi body in gland cells are larger and more secretory.Most of the glands of body are merocrine types.It originate from all three germinal layers.(ecto,meso and endoderm). Liver is the largest gland of the body and lined by glandular epithelium.

Types of glands:

(A) On the basis of number of cells

(i) Unicellular gland:

It consists of unicellular gland cells which are called as goblet cells

It consist of unicellular gland cells which are called as goblet cells or chalice cells. They secrete mucous and found in mucosa of intestine and stomach.Mucous lubricates the food for easy peristalsis. Their life span is about 2-3 days.

(ii)Multicellular gland: