To study and identify the given zoological specimens

Aim: To study and identify the given zoological specimens

 Materials Required: Models, slides or pictures of:

Pituitary gland, thyroid gland, adrenal gland, testis gland, ovary gland

Bones of forelimb, bones of leg, pectoral girdle, pelvic girdle

TS of kidney, TS of stomach, TS of small intestine (ileum), TS of lung

Observation:

Pituitary gland

(i)                 It is also known as the hypophysis. It is a pea-sized endocrine gland situated at the base of our brain.

(ii)                It is often referred to as the ‘Master Gland’

(iii)             It has three main parts: Anterior pituitary, Intermediate pituitary and Posterior pituitary.

(iv)             Intermediate pituitary is absent in adult human.

(v)               The anterior pituitary syntheses and secretes hormones like Human Growth Hormone (HGH), Luteinising Hormone (LH), Melanocyte-Stimulating Hormone (MSH) etc.

(vi)             The posterior pituitary stores and secretes ADH and Oxytocin.

 

Thyroid gland

(i)                 The thyroid gland is a ductless endocrine gland situated in the anterior of the neck.

(ii)               It roughly resembles the shape of a butterfly.

(iii)             It secretes two hormones:  Triiodothyronine (T3) and Thyroxine hormone (T4).

(iv)             It consists of two lobes and parathyroid glands are present on their posterior surfaces.

 

 

 

 

Adrenal gland

(i)                 The Adrenal Glands are found on top of each kidney.

(ii)               The right gland is pyramidal in shape and the left gland is semi-lunar in shape.

(iii)             There are three layers of adrenal cortex called zones.

(iv)             Zona glomerulosa – It secretes mineralocorticoids like aldosterone

(v)               Zona fasciculata – It is responsible for producing corticosteroids like cortisol

(vi)             Medulla region secretes catecholamines (such as adrenaline and noradrenaline).

 

 

 

Testes

(i)                 They are the primary sex organ of the male.

(ii)               They are the oval bodies, around 1.5 to 3 inches in length.

(iii)             They are present in the scrotal sac outside the body.

(iv)             They produce male sex hormones and sperms.

(v)               Seminiferous tubules are present in the testes.

 

 

 

Ovaries

(i)                 They are the primary sex organ of the female.

(ii)               These organs are situated one on both the side of the lower abdomen.

(iii)             Each ovary measures about 2 to 4 cm in length which is then connected to the uterus and pelvic wall through ligaments.

(iv)             They produce female sex hormones and ovum.

(v)               Ovary has two zones – outer cortex and the inner medulla.

(vi)             The cortex consists of various ovarian follicles in different stages of development.

 

 

 

Bones of forelimb

(i) It is made up of bones consisting of humerus, radius and ulna, carpals, metacarpals and phalanges.

(ii) Humerus is a straight bone with a long shaft, and forms the upper arm.

(iii) The head of the humerus fits into the glenoid cavity of the pectoral girdle.

(iv) Radius-ulna consists of 2 (two) separate bones of the forearm namely radius and ulna.

(v) Carpals consist of 8 (eight) small bones arranged in two rows. It forms the wrist.

(vi) Metacarpals are made up of 5 (five) long bones forming the palm of hand.

(vii) Phalanges consist of 2 (two) in the thumb and, 3 (three) bones in the remaining four fingers, thus totalling 14 (fourteen) bones.

 

 

 

Bones of hind-limb

(i) It is made up of femur, tibia and fibula, patella (knee cap) tarsals, metatarsals, phalanges.

(ii) The femur is the longest bone. The head of femur fits into the acetabulum of the pelvic girdle.

(iii) Tibia-fibula consists of two separate bones namely tibia and fibula and is present in the shank region of leg.

(iv) There are 7 (seven) tarsal bones, which are arranged in two rows to form the ankle.

(v) Metatarsals consist of 5 (five) bones and form foot.

(vi) Phalanges consist of 2 (two) bones in big toe and three bones in each of the remaining toes thus totalling 14 (fourteen) bones.

 

 

 

Pectoral girdle

(i) It consists of a clavicle and a scapula.

(ii) Scapula is a large triangular flat bone with a slightly elevated ridge called spine. The spine projects as a flat, expanded process called the acromion.

(iii) The clavicle is a long slender bone with two curvatures. The clavicle articulates with the acromion.

(iv) Below the acromion is a depression called the glenoid cavity, for articulation of the head of the humerus to form the shoulder joint.

 

 

 

Pelvic girdle

(i) It consists of two halves.

(ii) Each half is formed by the fusion of three bones - ilium, ischium and pubis.

(iii) At the point of fusion of the above bones is a cavity called acetabulum to which the thigh bone articulates.

(iv) The two halves of the pelvic girdle meet ventrally to form the pubic symphysis.

 

TS of Kidney

1.      The glomerular capsule surrounds the glomerulus.

2.      There is a cavity called the glomerular capsular space (Bowman’s / urinary space).

3.      The kidney filtration apparatus is formed by three layers of tissue; endothelium of the glomerular capillaries, glomerular basement membrane (GBM) and podocytes (visceral layer of renal capsule).

4.      Thick descending limb of the Henle’s loop and the distal tubule are composed of simple cuboidal epithelium.

5.      In the vascular pole of the nephron, collection of cells called the juxtaglomerular apparatus (JGA) is present.

 

 

TS of Stomach

1.      The stomach wall consists of 4 layers of tissue: Serosa, muscularis externa, submucosa and mucosa.

2.      The inner wall has folds known as rugae, or gastric folds.

3.      Gastric mucosa. It is formed by a layer of surface epithelium and an underlying lamina propria and muscularis mucosae. The surface epithelium is a simple columnar epithelium.

4.      Gastric pits are formed by invaginations of the surface epithelium. Gastric pits connect to gastric glands.

5.      Gastric glands are long, branched, tubular structures, present in the lamina propria.

 

 

 

TS of Small Intestine (Ileum)

 

1.      Ileum is the last part of the small intestine.

2.      The mucosa of the ileum consists of simple columnar epithelium comprising of enterocytes and goblet cells.

3.      Mucosa: Simple columnar epithelium; also contains Peyer's patches

4.      Submucosa: Contains nerves and blood vessels

5.      Tunica muscularis: Circular and longitudinal muscle layers

6.      Tunica serosa: Simple squamous epithelium

 

 

TS of Lung

1.      Lumen of the bronchioles can be seen as an empty space with irregular circular shape or with tapering ends.

2.      Most of the respiratory epithelium is ciliated pseudostratified columnar epithelium.

3.      The ciliated cells control the actions of the mucociliary escalator, a primary defence mechanism of the lungs that removes debris.

4.      Goblet cells are goblet-shaped and are filled with mucin granules.

5.      The basal cells connect to the basement membrane and provide the attachment layer of the ciliated cells and goblet cells.