Question

Describe anatomical structures involved in spermatogenesis and maturation of the sperm physiologically (location, function, tissues and cells involved, how it takes place, etc)

Diagnostic test of the heart, when you have heart problems the doctors give you an EKG; talk about the EKG and relate it to the operation of heart (systole, diastole, functional anatomy, etc)

Answer 1

Spermatogenesis-

Spermatogenesis is the process in which spermatozoa develop from male germ cells(Spermatogonia) in the seminiferous tubules of the testis

Location:Seminiferous tubule-Seminiferous tubules are present within the testes.This is the specific site of meiosis of Spermatocytes occur and the subsequent Formation of spermatozoa(Male Gametes)Occur

Seminiferous Tubules contains-

1.Male Germ Cells-Spematogonia

2.Sertoli cells(Nurse cells)

HYPOTHALAMUS-----Gonadotropin stimulating Hormone(GnRh)--------------Anterior Pituitary---Gonadotropins-

a)FSH(Follicle stimulating Hormone)

b)LH(Leutinizing Hormome)

LH stimulates Leydig cell  production---which produce testosterone---Stimulates Spermatogenesis.

FSH stimulates Sertoli cells----Nourishment of Sperm cells and creating Blood testis Barrier through tight Junctions.

there are three phases in spermatogenesis:

1. Spermatocytogenesis (Mitosis)

2. Meiosis

3.Spermiogenesis.

On stimulation By Testosterone,

Spermatogonia---------Mitosis and Enlarges-----------------Primary Spermatocytes (2N)

Primary Spermatocytes-----Meiosis 1----------Secondary Spermatocytes(N)(2 Secondary Spermatocytes from 1 Primary Spermatocytes)

Secondary Spermatocytes(N)----Meiosis 2-----------Spermatids.(2 Spermatids from 1 Secondary Spermatocytes)

So 1 Spermatogonia---------------4 Spermatids.

Spermatids ----------------------------------Spermatozoa (By process called Spermiogenesis)

Functions of Sertoli cells-

Sertoli cells nourishes Sperm

Also,

Sertoli cell tight junctions Prevents  the passage of steroids,large molecules, and ions into the seminiferous tubule and Forms the blood-testis barrier.
The blood Testes Barrier Protects germ cells residing in the adluminal compartment from the circulatory and lymphatic systems, and  with local immune suppression.This provide an immunoprivileged microenvironment for the  Developing spermatoctyes to complete meosis and form the Spermatozoa

Q2.EKG

EKG(ECG) Electrocardiogram is a Graphical representation of electrical activity of Heart.This can be used as a test to identify any Abnormality in the Heart.

The different Waves formed in the ECG are-

1.P wave -This Corresponds to Atrial Depolarisation

(Small wave with Moderate Velocity-Because atrial tissue is less compaerd to ventricular Tissue and Lacks the fast conducting Purkinje System)

2.PR Segment:Isoelectric line corresponds to AV Node Depolarization.

Here SInce AV node depolarisation is very small,ECG machine cannot detect it so iso electric line is formed

3.QRS complex-Corresponds to Ventricular Depolarization-

a)Q-small but high velocity Negative wave,Corresponds to Depolarisation of interventricular Septum)

b)R-Large high velocity positive wave,Corresponds to Major Ventricular Depolarization

c)S wave-Small High velocity Negative Wave .Corresponds to Basal Ventricular Depolarization

4.ST Segment:Iso electric line,Time period between Complete Depolarization of Ventricles and Beginning Of Ventricular Repolarization

5.T wave:Corresponds to Ventricular Repolarization.Moderate velocity Positive Wave.

Atrail Repolariztion Occur during Ventricular depolarization ,Hence it is masked by Ventricular Depolarization So not detected In ECG as indepenedent.