Structure and functions o blood

 

Adrenal Gland and its Hormones

 

Adrenal Gland

Location:- These are a pair of glands, one associated with each kidney.

Structure:-They have an inner medulla and outer cortex

Adrenal cortex:-

All the hormones secreted by this region are steroid hormones, which are all based on cholesterol. Secretary cells, secrete steroid-based hormones, and contain triglyceride droplets.

The cortex can be divided into three regions:

1.     Zona glomerulosa - secretes mineralcorticoids

2.     Zona fasciculate -   secretes glucocorticoids

3.     Zona reticularis -    secretes sex hormones (androgens). and small amounts

     of glucocorticoids.

 

 1.     Zona glomerulosa:-

the outermost zone of the adrenal cortex secretes mineralcorticoids. These hormones are important for fluid homeostasis. These include aldosterone, which regulates absorption/uptake of K+ and Na+ levels in the kidney.

The secretory cells are arranged in irregular ovoid clusters that are surrounded by trabeculae which contain capillaries. The nuclei stain strongly, and the cytoplasm is less pale than that of the next zone, the zona fasciculata, as there are fewer lipid droplets in these cells.

 

2.     Zona fasciculate:-

The middle zone of the adrenal cortex secretes glucocorticoids which are important for carbohydrate, protein and lipid metabolism. An example is cortisol which raises blood glucose and cellular synthesis of glycogen. Its secretion is controlled by a hormone from the pituitary - ACTH.

The secretory cells are arranged in cords, often one cell thick, surrounded by fine strands of supporting tissue.

The nuclei of these cells stain strongly, and the cytoplasm is rich in sER, mitochondria and lipid droplets. The cytoplasm looks pale and 'foamy' due to the presence of lipid droplets.

 

3.     Zona reticularis:-

 The innermost layer of the cortex secretes sex hormones (androgens). and small amounts of glucocorticoids. These hormones are secreted by the inner zone of the cortex, which is called the zona reticularis.

Some brown pigment is seen in some of these cells - this is lipofuscin, probably an insoluble degradation product of organelle turnover - an 'age' pigment. The cytoplasm of the cells in this region stains more darkly and contains fewer lipid droplets.

 

Adrenal medulla:

This region of the adrenal glands contains basophilic staining cells, with a granular cytoplasm and no stored lipid. It also contains many venous channels which drain blood from the sinusoids of the cortex, pass through the medulla, and drain into the medullary vein.

This is because these cells are actively secreting the peptide-based hormones - nor-adrenaline and adrenalin (catecholamines), which are stored in the granules.

Secretion of these hormones is controlled by the sympathetic nervous system. The targets of these hormones are the adrenergic receptors in the heart, blood vessels, bronchioles, visceral muscle, skeletal muscle, and in the liver, where they promote glycolysis (breakdown of glycogen).

The Pituitary Gland and its hormones

b. 

The Pituitary Gland:

Endocrine tissue is made up of cells that produce secretions which are poured directly into blood. Endocrine cells lie in close apposition to blood capillaries or sinusoids. Secretions of endocrine cells are called hormones. Hormones travel through blood to target cells and influence their function

 

The Endocrine Glands (Ductless glands)

1.     Pituitary (hypophysis)

2.     Adrenal gland (suprarenal)

3.     Thyroid gland

4.      Parathyroid gland

 

The Pituitary Gland: also called as “Master endocrine gland”.

The pituitary gland has the following two major Parts:

a. Adenohypophysis

b.  Neurohypophysi

 

a. Adenohypophysis:-(Anterior Pituitary): consist of the following parts

1.     pars distalis,

2.     pars intermedia

3.     pars tuberalis.

 Neurohypophysis :-  (Posterior Pituitary): consist of pars nervosa, infundibular stalk & median eminence.

 a. Adenohypophysis

1.  Pars Distalis:

Cells are arranged as irregular cords in between thin-walled fenestrated sinusoids.

Consists of 2 major group of cells: chromophils & chromophobes.

Chromophils are of 2 types: basophils & acidophils.

2. Pars Intermedia: Poorly developed in humans. Consists mainly of basophils.

Presence of colloid filled vesicles. Some cells produce melanocyte stimulating hormone (MSH).

3. Pars Tuberalis: Consists of chromophilic (mostly basophilic) & chromophobic cells.

 b. Neurohypophysis

Consists of:  Numerous non-myelinated nerve

Produce 2 hormones:

1.     Oxytocin

2.     Vasopressin

 

Hormones of Adenohypophysis

Type of chromophil	Class	Secretory Product	Target Organ
Acidophil	Somatotrophs (about 50%)	growth hormone (GH, also known as somatotrophin, STH)	General, but a major target is the chondrocytes in epiphyseal growth plates. Promotes growth (together with insulin like growth factors)
	Mammotrophs (about 20%)	prolactin (PRL)	Milk producting tissue (alveolar cells) in the breast
Basophil	Corticotrophs (about 20%)	ACTH (Adrenocorticotrophic hormone,) also known as corticotrophin. Melanocyte-stimulating hormone (MSH)	Trophic (trophic - from the greek - to nourish)- general action - promote growth and secretory activity in other endocrine glands. ACTH target is the corticosteroid cells of the adrenal cortex. MSH target is the melanocytes. TSH target is the follicular epithelial cells of the thyroid. FSH target is the follicular cells of the ovaries, to promote growth of follicles, or the sertoli cells of the testes to promote spermatogenesis. LH target is developing follicles - promotes ovulation, or the Leydig cells of the testes - where it promotes secretion of adrogenens, aiding spermatogenesis. Three of these trophic hormones (TSH, FSH and LH) are glycoproteins, so they can be stained up by the technique PAS.
	Thyrotrophs (about 5%)	TSH (thyroid stimulating hormone), also known as thyrotrophin
	Gonadotrophs (about 5%)	gonadotrophins: FSH (follicle stimulating hormone) and LH (Lutenising hormne).

 

Posterior  lobe of Pituitary. gland- Neurohypophysis

The posterior pituitary looks very different to the anterior pituitary.  It contains non-myelinated axons which are the neurosecretory cells. The cell bodies of these cells are located in the hypothalamus.

It only secretes two hormones:

Antidiuretic hormone (ADH) which acts on the kidney, and oxytocin, which acts on the uterus.

 

 

 

 

 

MCQ - Physiology

 MCQ - Physiology 

 

. ------ is the neurotransmitter substance present in synaptic vesicles

a.     Acetic acid

b.     Pyruvic acid

c.      Acetyl Colin -A

d.     Adrenalin

Completion of cardiac cycle required …………time.                       

a) 0.4 sec         b) 0.8 sec    c) 0.2 sec                          d) 0.3 sec

 

When carbon dioxide binds to hemoglobin, a molecule called ---------is formed.

a. carboxy hemoglobin

b. carbonic acid

c. carbaminohemoglobin

d. oxy hemoglobin

 

--------------- is the functional unit of nervous system.

a.     Nephrons

b.     Sarcomere

c.      Neuron

d.     Serrtoli  cells

 

What is sarcomere?

a) Part between two H line

b) Part between two A line

c) Part between two Z line

d) Part between two I band

 

 Clotting of blood is due to --------

a.     Erythrocytes                 

b.     Leukocytes                   

c.      Platelets

d.     Lymphocytes

 

In person, when  the sugar lever is higher than normal level is termed as----

        a) Aglycemia                           b) Hyperglycemia

        c) Homoglycemia                     d) Heteroglycemia

. ………. Vitamin is not fat soluble vitamin.

        a) Vit-A                b) Vit -E     c) Vit- B                         d) Vit-D

 Terminal knob of neurons are termed as  -------

a.     Dendrites

b.     Teladendron

c.      Axon

d.    Synaptic knob

 Blood pressure is measured by --------------

a. stethoscope

b. thermometer

c. sphygmomanometer

d. analyzer 

 

Rickets caused due to deficiency of ……………..vitamin.

 a)  Vit C     b)  Vit D     c)Vit K                 d) Vit E

 

Nephrons are present in----------.

a.     Liver

b.     Pancreas

c.      Kidney

d.     Nervous system

The junction between the axon terminal of one neuron and the dendrite terminal of the other neuron is---------------

1.     connection

2.     junction

3.     synapse.

4.     joint

 

The Dark  band of a skeletal muscle are known as

a.     Isotropic or I –band

b.    Anisotropic or A-band

c.      Hansen’s or H-zone

d.     Z-line

Gastric HCl is Secreted by …………..

a) Oxyntic cell b) Serous cell         c)Kuffers cells       d) islets of Langerhans

A respiratory pigment found in a mammal is---------

a)     Hemocyanins

b)    Hemerythrins

c)     Hemoglobins

d)    Hirudin

Muscles get fatigue due to the accumulation of

a) Lactic acid

b) ATP

c) Phosphate molecules

d) Carbon dioxide

 

 Blood pressure in healthy person is…………….mmhg.

          a) 140/160            b) 80/120    c) 120/80                 d) 90/60

 

 Rickets caused due to deficiency of ……………..vitamin.

          a)  Vit C      b) Vit D      c)Vit K                 d) Vit E

 

Gastric HCL is Secreted by …………..

a)Oxyntic cell       b) Serous cell         c)Kuffers cells     d) Islets of Lagerhans

 

………… is waste product produced in Ornithinecycle.

a) Urea                  b) Ammonia                   c. Nitrogen           d. Uric acid

 

. …………. is antifertility vitamin.

        a) vit A                 b) Vit K                c) Vit E                 d) Vit D  

 

 

. --------------- is the functional unit of nervous system.

a.     Nephrons

b.     Sarcomere

c.      Neuron

d.     Serrtoli  cells

 

What is sarcomere?

a) Part between two H line

b) Part between two A line

c) Part between two Z line

d) Part between two I band

 

 

 Clotting of blood is due to --------

a.     Erythrocytes                 

b.     Leukocytes                   

c.      Platelets

d.     Lymphocytes

 

 

 The junction between the axon terminal of one neuron and the dendrite terminal of the other neuron is---------------

a.      connection

b.     junction

c.      synapse.

d.     joint

 

. The light band of a skeletal muscle are known as

a.     Isotropic or I –band

b.     Anisotropic or A-band

c.      Hansen’s or H-zone

d.     Z-line

 

  In case, blood sugar level Crosses the 100 mg/ml of blood the condition is known as……

        a) Aglycemia                           b) Hyperglycemia

        c) Homoglycemia                     d) Heteroglycemia

 

. ………. Water soluble vitamin.

        a) Vit A                b) Vit B      c) Vit k                           d) Vit D

 

Branched processes arrases from cell body are -------

a.     Dendrites

b.     Teladendron

c.      Axon

d.     Synaptic knob

 

 The major protein present in thick filament of skeletal muscle fiber is

a.     Actin

b.     Troponin

c.      Myosin

d.     Tropomyocin

  . …………. is anti-sterility  vitamin.

a) vit -A                    b) Vit- K                 c) Vit -E             d) Vit -D  

 Nucleated RBCs are found in-------

a.     Human  

b.     Cow

c.      Camel

d.     Cat     

 Respiratory pigment found in mammal is---------

a)     Hemocyanins

b)    Hemerythrins

c)     Hemoglobins

d)    Hirudin

 Muscles get fatigue due to accumulation of

a) Lactic acid

b) ATP

c) Phosphate molecules

d) Carbon dioxide

 

 In resting neuron negative charge on inner side of axon is due to -----------------

a. potassium

b. magnesium

c. sodium

d. chloride

 The release of chemical messengers in the synapse is called ----------

a.     Neurotransmitter

b.     Activator

c.      Generator

d.     Inhibiter

 Completion of cardiac cycle required …………time.                          

a) 0.4 sec                   b) 0.8 sec    c) 0.2 sec                          d) 0.3 sec

 

  Exchange of O₂ and CO₂ at respiratory surface across through  passive

a) Active transport                  b) Passive transport      

c) Simple diffusion                   d) Osmosis

 

  Clotting of blood is due to --------

a.     Erythrocytes                 

b.     Leukocytes                   

c.      Platelets

d.     Lymphocytes 

 

Blood pressure in healthy person is…………….mmhg.

a) 140/160                 b) 80/120    c) 120/80                 d) 90/60