Lab Exercise # 6Zoo- 145. The digestive system is a collection of organs that work together to digest and absorb food. Digestion is the process the body

Lab Exercise # 6 Zoo- 145

• The digestive system is a collection of organs that work together to digest and absorb food.

• Digestion is the process the body uses to break down foods into molecules that the body can use for energy and nutrients


Organs of the digestive system

The Digestive System

The digestive system consist of oral cavity with its accessories parts and thedigestive tract with its accessories glands

The digestive tract or Gastro Intestinal Tract (GIT) includes:

1. Oesophagus

2. Stomach

3. Small intestine

4. Large intestine

Every section through the digestive tract shows that each of the part is composed of four different layers


Serosa Musculature (Muscularis)

Submucosa Mucosa

Oesophagus is a muscular tube connects the pharynx with the stomachIts wall consist of four layers

Serosa: Outermost layer is composed of Simple Squamous Epithelium

Musculature: Three layers thick, two layers of Longitudinal Muscle Fibers and a layer in between is composed of Circular Muscle Fiber

Submucosa: It is composed of Connective tissue

Mucosa: It is composed of stratified squamous epithelial


The Oesophagus


Stomach is the dilated segment of the digestive tractThe wall of the stomach is formed of four layers:

Serosa: It is composed of connective tissue and squamous epitheliumMusculature: Two layers, one each from longitudinal (LMF) and circular muscle fibers (CMF)Submucosa: It is composed of connective tissueMucosa: It is thick and lined marginally with simple squamous epithelium and peptic and oxyntic cells. Peptic cells are secreting peptic enzymes and oxyntic cells secrete HCL acid


The Stomach


Liver Is the largest metabolic organ in the body

the liver formed of a stroma of connective tissue and parenchyma of liver cells (hepatocytes)All of the cells in the liver are called hepatic cells and these are arranged in lines in the unit of liver called hepatic lobules (Hexagonal shape). Each such line of the hepatic cells is called hepatic strand. The space in between hepatic strands is filled with blood and it is called hepatic sinusoid. In the centre of each hepatic lobule there is hole called central vein


The Liver


The connective tissue septa cornered between 3 hepatic lobules is called portal spaceor area, which contains the following structures:

1- Branch of hepatic artery2- Branch of portal vein3- Bile ductule4- Lymph vessel

The Liver


T. S.

The Testis is both an exocrine and an endocrine organ.

The exocrine portion consists of a series of highly coiled seminiferous tubules that make sperm

the endocrine portion consists of specialized cells called interstitial cells (also called Leydig cells) that secrete testosterone.

The Interstitial Cells lie in the connective tissue between adjacent coils of seminiferous tubules

Two Testes Different tubules

Accessory Glands

Male Reproductive System

Epididymis

Vas Deference

Ejaculatory duct

Seminal Vesicles

Prostate Gland

Cowper’s Gland



The Testis

Testis is composed of functional units termed seminiferous tubules. Seminiferous tubules are bound together with connective tissue termed as inter tubular connective tissues. The outer layer of the testis is called tunica albugenia. Spermatogonia are transformed meiotically into primary spermatoctes then in secondary spermatocytes and spermatids. Finally spermatids are transformed into sperms.

The seminiferous tubule is highly convoluted tubule lined by the following cells:

1- Spermatogenic cells: The spermatogenic cells consist of five morphologically distinct classes of cells: Spermatogonia, Primary Spermatocytes, secondary spermatocytes, spermatids, and spermatozoa .

2- Sertoli cells: Sertoli cell is supporting cells, columnar cells with irregular nuclei. These cells are extend from basement membrane to the lumen of the seminiferous tubule.



Ovary Oviduct(Fallopian Tube)

Uterus

Female Reproductive System

The Ovary is a large, almond-shaped structure covered by germinal epithelium

The ovary consist of : 1- Peripheral cortex Primordial follicles. Primary follicles. Secondary follicles. Growing follicles. Mature Graaffian follicles. Atretic follicles. Corpus luteum


2- Central medullaThe medulla of ovary is small part compared to the cortex, its connective tissue contains many spiral arteries and convoluted veins.

Ovary is covered by a simple Cuboidal Epithelium known as the germinal epithelium (GE).

Beneath the Germinal Epithelium lies a tough connective tissue coat, the Tunica Albuginea (TA).

The tunical albuginea outlines the outer part of the Ovary, the cortex, in which the developing follicles lie.

The core of the Ovary, called the Medulla (M), is made up of connective tissue through which blood vessels (V) pass


The Ovary


Micro anatomically every ovary is composed of marginal layer of epithelium, peritoneal layer and then a germinal layer which are meitotically transformed into primary oocytes then secondary oocytes and graaffian follicles. Finally graaffian follicles are grown into mature ova. The space left by graaffian follicle is called corpus luteum which acts as an endocrine gland. The tissue that binds the cells together in the ovary is called stroma and it is a combination of muscular tissue with connective tissue.


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Lab Exercise # 6Zoo- 145. The digestive system is a collection of organs that work together to digest and absorb food. Digestion is the process the body