Human reproduction

 Chapter-3 HUMAN REPRODUCTION

Events of Human Reproduction

Gametogenesis : formation of gametes.

Insemination : Transfer of sperm in female genital tract.

Fertilization : fusion of sperm and ovum.

Implantation : attachment of blastocyst with uterine wall for further development.

Gestation : Embryonic development

Parturition : Delivery of the baby. 

The Male reproductive system

1. Penis :

a. Urination

b.     Sexual intercourse

c.     Corpus cavernosum- spongy tissue that fills with blood to make penis erect

d.      Glans- the head, end of penis

e.     Foreskin

i.  Covers glans,

ii.  May be removed surgically in an operation

2.  Scrotum   

a.  Located behind penis

b.  Contains two testes

c.  Temperature sensitive (Sperm must be made in cooler conditions i.e, 2-3⁰ C lower than body temperature) 

3. Testes

a.  Sperm is produced by the seminiferous tubules due to FSH

b.  Testosterone is produced by Leydig cells due to LH

Sertoli cells : Provide nutrition to developing germ cells.

Interstitial cells / Leydig cells : Synthesize & secrete testicular hormone called androgens.

ACCESSORY DUCTS :

Epididymis:    Stores sperm until they have matured.

Vas deferens: Tube that leads from the epididymis to the urethra. Many sperm cells are stored here too.  

ACCESSORY GLANDS :

Prostate gland:     Provides an alkaline fluid that can protect sperm from harsh vaginal acids.

Seminal Vesicles:    Produce food for sperm. Food "Fructose"

Cowper's gland:      Produces clear lubricating fluid

SPERM

SEMINIFEROUS TUBULES

Head : It contains a elongated haploid nucleus, covered by acrosome. It filled with hydrolytic enzymes to dissolve the membrane of ovum for fertilization. Neck : It contains two centrioles helps in first cleavage division of zygote. Middle Piece: contains numerous mitochrondria which produce energy for movement of tail that facilitate sperm motility essential for fertilization Tail : helps in Sperm movement

Spermatogonium : it is diploid contains 46 chromosomes.   Primary Spermatocyte (2n): it complete 1st meiotic equal division (reduction) & forms 2 secondary spermatocytes.   Secondary spermatocytes : it is haploid, undergo the 2nd meiotic div to produce four equal haploid spermatids.   Spermatids : They transformed into spermatozoa (sperms) by the process called spermiogenesis with the help of FSH.   Spermiation : After spermiogenesis, sperm heads become embedded in the sertoli cells and finally released from seminiferous tubules by the process of spermiation.

The Female Reproductive System :

Ovary: i) Each ovary contains immature ova (eggs) in follicles. ii)  Females born with lifetime supply of eggs (250,000-400, 000 in each ovary) iii)  Ovaries release ovum -. Almost all ova degenerate between birth and puberty. iv)  Approx. 400 eggs will be ovulated over woman's life. v)  Egg is the largest human cell. vi)  Ovaries are located lower abdomen. 1 left and 1 on the right.   Fallopian tubes i) Two thin tubes attached to the upper sides of uterus ii)  Tubes terminate near the ovaries but are not attached iii) "Fimbriae" are finger-like structures on the end of each tube iv) Tubes conduct egg to uterus by use of small hairs called "cilia" v) Fertilization of ovum takes place in the ampullary- isthmic junction of the fallopian tubes. Egg viable for only 24-48 hours after ovulation.

Uterus: i)Pear-shaped organ located in lower abdomen. ii)Muscles(myometrium) stretch to allow baby to develop. Oxytocin starts labor contractions. iii)Lining of uterus (endometrium) thickens with blood-rich tissue due to progesterone. iv)Endometrium supports embryo/fetus during growth. v) Placenta It is the interface between baby and mother. If not pregnant, lining breaks down and is discharged from body through vagina. This is menstruation (period). vi) Cervix connects uterus to vagina. Like a door that opens during ovulation. Cervical mucous closes the door at all other times.

EXTERNAL GENITALIA:

Vagina (Birth canal) :

  ·   Menstrual blood leaves the body, Organ of intercourse , Muscular stretches to allow a baby to grow

  ·   Vaginal opening partly remains closed by thin membrane of tissue called hymen. May be stretched or torn during any physical activity or first intercourse.

Cervix:

·   Located at inner end of vagina, Opening of uterus into vagina ,

·   Mucous prevents bacteria and viruses from entering uterus, Lets sperm into uterus after ovulation

·   Where baby also passes through during vaginal birth

  Labia: Two (2) layers of skin, which fold over the opening to vagina and urethra

      ii)  Inner labia (labia minora)               iii)Outer labia (labia majora)

·   Pubic hair grows on outer labia

 Clitoris: Small organ, 5 to 10 millimeters long; Located at junction of inner labia near front of body Contains erectile tissue& sexually sensitive.

Mons pubis :Cushion like fatty tissue covered by skin and pubic hair

Gametogenesis & its hormonal regulation : 

FSH and LH from the pituitary:	FUNCTION / PRODUCTION
Hormone	In Females	In Males
FSH Controls à	Eggs + Estrogen (Follicular development)	Spermiogenesis
LH Controls à	Ovulation + Corpus Luteum	Testosterone (Spermatogenesis)

 Differentiate between: Spermatogenesis and Oogenesis :

Spermatogenesis	Oogenesis
Produces male gametes (sperm)	produces female gametes (oocytes)
–occurs in the seminiferous tubules (in testes)	–occurs in the ovaries
–occurs throughout life after puberty	occurs after puberty until menopause
may produce 3,00,00,000 per day	–humans normally produce one oocyte during each ovarian cycle
Primary spermatocyte divide equally to form two similar secondary spermatocytes	Primary otocyte divide unequally to form one large secondary oocyte and a small polar body
One spermatogonium produces 4 functional spermatozoa	An oogonium produces one functional ovum and 3 non functional polar bodies

Periodic classification of elements Quiz-1

Periodic classification of elements

Quiz

 

1. Newlands relation is called
   1.   Law of Octaves
   2.   Periodic Law
   3.   Atomic Mass Law
   4.   Musical Law
2. Upto which element, the Law of Octavees was found to be applicable.
   1.   Oxygen
   2.   Calcium
   3.   Cobalt
   4.   Potassium
3. In Mendeleev’s Periodic Table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the Periodic Table later?
   1.   Oxygen
   2.   Chlorine
   3.   Silicon
   4.   Gemanium
4. At the time of Mendeleev, the number of elements known was
   1.   65
   2.   63
   3.   64
   4.   62
5. The arrangement of elements in the Modem Periodic Table is based on their
   1.   increasing atomic mass in the period
   2.   increasing atomic number in the horizontal rows
   3.   increasing atomic number in the vertical columns
   4.   increasing atomic mass in the group
6. Where would you locate the element with electronic configuration 2, 8 in the Modern Periodic Table?
   1.   Group 8
   2.   Group 18
   3.   Group 2
   4.   Group-10
7. Element ‘X’ forms a chloride with the formula XCl2, which is a solid with high melting point. X would most likely be in the same group of the periodic table as:
   1.   Si
   2.   Mg
   3.   Al
   4.   Na
8. Which of these belong to the same period?
   Element A B C
   Atomic number 2 10 5
   1.   A, B
   2.   B, C
   3.   C, A
   4.   A, B and C
9. Pick out the chemically most reactive elements from the given triads.
   Li, Na, K F, Cl, Br
   1.   Li and F
   2.   Li and Br
   3.   K and F
   4.   K and Br
10. Which among the following elements has the largest atomic radii?
    1.   Na
    2.   Mg
    3.   K
    4.   Al
11. Which of the following elements does not lose electron easily?
    1.   Na
    2.   F
    3.   Mg
    4.   Al
12. Chlorine (17) belongs to which group and period
    1.   17,3
    2.   17,4
    3.   16, 4
    4.   16, 3
13. Which of the following elements will form an acidic oxide?
    1.   An element with atomic number 7
    2.   An element with atomic number 3
    3.   An element with atomic number 12
    4.   An element with atomic number 19
14. The element with atomic number 14 is hard and forms acidic oxide and a covalent halide. to which of the following categories does the element belongs?
    1.   Metal
    2.   Metalloid
    3.   Non-metal
    4.   Non
15. An element 'X' belong to third period and second group of the modern Periodic table.
    (a) Write its electronic configuration.
    (b) is it a metal or non-metal?
    1.   (a) 2,8,2
       (b) Metal
    2.   (a) 2,8,1
       (b) Metal
    3.   (a) 2,8,2
       (b) Non-Metal
    4.   (a) 2,8,1
       (b) Non-Metal
16. The elements A, B and C belong to groups 1, 14 and 17 respectively of the Periodic Table. Which two elements will form ionic compounds?
    1.   A and B
    2.   A and C
    3.   B and C
    4.   None
17. An element X from group 2 of the Periodic Table reacts with Y from group 17 to form a compound. Give the formula of the compound.
    1.   XY2
    2.   XY
    3.   X2Y
    4.   (XY)2
18. An element ‘A’ belongs to the third period and group 16 of the Periodic Table. Find out the valency of A.
    1.   Valency = 6
    2.   Valency = 2
    3.   Valency = 1
    4.   Valency = 3

IRREGULAR FOOD HABIT AND ACIDITY

 

IRREGULAR FOOD HABIT AND ACIDITY

^{A Group of teachers in a Common training Programme went for lunch in break. One of them, named Sandeep, felt Stomach Ache. Nurse madam was immediately called ,}

^{She said that Mr. Sandeep has acidity problem. Mr Sandeep said that he had taken heavy oily food for breakfast. He felt relaxed soon after he was given ANTA-ACID(milk of magnesia, baking soda etc) .}

 ^{And also learnt about that one must have healthy food to avoid common digestion problems}

^{Q.1. 1) The main cause of acidity is}   

^{a) Bad food habit}                                                           

^{b) Heavy oily and spicy food}

^{c)Excess secretion of HCl in stomach}                        

^{d) smoking habit}

^{Ans- c)}                      

 ^{Q.1.2) A Country has a high number of acidity problems.  Can the following questions about acidity be answered by scientific experiments? Circle YES OR NO for each question.}

^{a)Can this question about acidity be answered by scientific experiment?    (YES/NO)}

^{b)what would be the effect of acidity after taking anta-acid?     (YES/NO)}

^{c)how much should a person visit to the doctor?  (YES/NO)}

    ^{Ans- a) YES,     b)YES,      c) NO}

^{Q)1.3-Which one of following is a function of anta-acid?}

^{a)To reduce the effect of acid}

^{b)To neutralize excess acid secreted by histamine}

^{c)To make person relaxed due to chemical reaction}

^{d)No effect}

^{Ans-  both  a) and b)}         

^{Q.1.4) What food habits are to be developed to avoid acidity?}

^{Ans……………………………………………………………….}

^{Answer- a) taking food timely, avoid oily and junk food, regular exercise-}       

Artificial sweetening agents

 

 Artificial sweetening agents

Artificial sweetening agents like saccharin, aspartame, sucralose, alitame(are artificial sweeteners) do not have any nutritional value. They do not provide calorie intake. Artificial sweeteners have a very great importance to diabetic persons and to the persons who need to control intake of calories. Some artificial sweeteners like aspartame can be used only in cold foods and soft drinks because they are not stable at high temperatures. Alitame is about 2000 times sweeter than sucrose.

saccharin- is Ortho-sulphobenzimide and fist popular artificial sweetening reagent, discovered in 1879. it is about 550 times as sweet as cane sugar. it is excreted from the body in urine unchanged

Aspartame- is the most successful and widely used artificial sweetener. it is about 100 times as sweet as cane sugar. it is methyl ester of dipeptide formed from aspartic acid and phenylalanine.

Alitame-is high potency sweetener, although it is more stable aspartame . the control of sweetness of food is difficult while using.

Sucralose- is trichloro derivative of sucrose. its taste and appearance like  sugar. it is stable at cooking temperature.

these 

Question 2.1 The purpose of using artificial sweetening agents is-

(A)          As a source of instant energy to the body.

(B)         To give sweet taste .

(C)         To provide intake of calories  .

(D)        Both (B) and ( C) .

Ans-B

Question 2.2  - Aspartame can not be used in hot tea because-

(A)    It is stable at cooking temperature .

(B)    It decomposes in hot tea.

(C)    It does not provide calorie.

(D)   All of the above.

 Ans-B

Question 2.3 --------- is trichloro derivative of sucrose.

Ans- Sucralose

ORS

  Oral rehydration Salts

ORS means Oral rehydration Salts we are taking in the form of solution to become more energetic during the summer seasons specially. Because more water and salts or ions from our body is released due to sweating and weakness caused. Some time extra water and ions are released from the body due to diarrhea, dysentery, vomiting also.

Physiologically the ORS provides us ions to maintain the nervous system transmission smoothly by Na, Cl, and K pumps during the nerve impulse as shown in the diagram. Water is the main component of blood which enhances the capacity of transportation along with these ions which are present in the form of ORS solutions. Hence we are prevented from internal organs failure also. That’s why Doctors are suggesting we keep this ORS in the form of first aid or keep it at home for personal safety purposes .

Question 1. Which one of them is essential for rehydration?

  (a)  Thumbs up

   (b)  Pepsi

   (c)  ORS

   (d)   Soft drink

Answer- c

Question 2. Ions essential for the maintaining of nervous system properly are

(a)  Cl, Ca and Mn

(b)  Ca, P and Mg

(c)   Na, K and Cl

(d)  Cl, Mn and Ca

      Answer -c

Question 3. True or False

        (i)     Soft drink rehydrates us due to we feel no thrusts.

        (ii)   ORS is exactly similar to common sarbat /sugar solution of India.

          Answer –Both (i) and (ii) are false                            

Question 4. Fill in the blank

      The full form of ORS is ………………

         Answer -oral rehydration salts

Question 5. Why ORS used as first aids?

      Answer – For rehydration, more energetic health, to maintain nerve cell function, preventing organ failure under dehydration condition, Refreshment, recharges us to perform more work, use as oral saline.