Gland and reproductive system

Glands and hormones

Glands are those cells which produce secretion called hormones that are released in the blood stream to reach their target sites

Hormones are the chemical messenger that travel inside our body through blood stream and control our body to function and perform its day to day activity.

Glands are divided in two types: endocrine glands and exocrine glands

Endocrine glands: these glands are ductless glands that mean that they pour their secretion directly in the blood stream. The secretion reaches its target site travelling through blood. Eg; pineal, pituitary, parathyroid, thyroid, thymus, adrenal, ovaries(female), testes(male).

Exocrine glands: these glands release their secretion with the help of duct at the specific sites. Eg; tear gland(lachrymal), salivary, mammary(female), live,r intestinal, urethral(male).

Heterocrine glands: these are the exceptional gland which poses both kinds of characteristics. Some secretions are released through duct while some secretions are released directly in the blood stream. Eg; pancreas and gonads.

What is the role of hormone is initiating reproductive system?

When the pituitary gland also called as master gland secrete follicle stimulating hormone (FSH), it stimulates the gonads (testes and ovary) to release testosterone and estrogen respectively. These hormones cause the physical change in human body to take place. Along with this testosterone and estrogen activates the testes and ovary to release their respective gametes, sperm and ova.

Reproductive phase in life of humans:

Reproductive phase in the life of a female: in female the reproductive phase starts at puberty with the time when the ovary releases it first ova and it lasts till the age of 45-50 years. With the onset of puberty ova start to mature. During the reproductive period the two ovaries start to release ova after each 28 days. Each ovary release an ovum alternately at the difference of 28 days. When the ovum is released it passes through the fallopian tube, during this period the uterus prepares itself for the situation in which egg gets fertilized and zygote is formed. In the presence of estrogen and progesterone the wall of uterus gets thick and gets enriched with lots of capillaries. This happens because the foetus settles in the uterus and the foetus gets nutirition from the mothers blood through the umbical cord. If there is no fertilization the uterus wall slowly breaks down and blood and mucous is released from the vagina. This process is called menstruation and it repeats at every 28 days in the form of a cycle.

Sex determination of boy or a girl

The genetic information of a person is carried in the nucleus of its cell. In the nucleus the information is present in the chromosomes in the form of genes. Genes carry the information from parents to offsprings. Sex chromosome of a female is XX while that of a male is XY. When the gamete are formed the mother gamete contain X chromosome gamete while the gametes of father will be of two type, one having X chromosome and another one having Y chromosome.

When X chromosome of female fuses with X chromosome of male a girl child is born while When X chromosome of female fuses with Y chromosome of male a boy child is born.

Adolescence and puberty

When a child takes birth the newborn is called infant till a year, when he starts moving he is called a toddler, then comes the phase of childhood and a fully mature person is called a adult, the time between childhood and adult is adolescence. adolescence is the time when the person is in the process of becoming an adult, who can control their emotions, can act in a society, have intelligence, and is sexually capable.

What is adolescence?

Adolescence is the age in which a person gains social, mental, emotional and sexual maturity. It is the basically the teen age (13 to 19 years). The time when a person faces lots of hormonal changes in his or her body. It is the transition phase from childhood to adulthood.

What is puberty?

Puberty is the time when a person male or female gains sexual maturity. By the end of puberty the person has fully developed reproductive (sex) organs. He/ she has developed all the secondary sex ogans. A boys is biologically ready to become a father and a girl is capable of becoming a mother.

Changes during puberty

Increase in height: during adolescence there is a sudden increase in the height of individual. Generally an individual reaches its maximum height by the end of adolescence.   

Change in physical features: there are many physical changes in an individual during adolescence, although the changes in male and female body are generally different from each other.

     Changes in male:

·         growth of  beard and moustaches

·         chest gets broad

·         development of pubic hair and hair in armpit

·         development in penis

·         enlargement of voice box

·         muscular development of body

    Changes in female:

·         growth of mammary gland and breast

·         pelvic region broadens

·         hips gets broader

·         development of pubic hair and hair in armpit

Change in voice: with the start of adolescence the voice box in case of male gets enlarged and thus the sound coming out of its get hoarse. In certain cases the voice box gets large enough that it can be noticed in the throat.it is also called as adam’s apple. 

Increased activity of sweat and sebaceous gland: the sweat and sebaceous gland gets activated. The sweat gland produces lots of sweat, similarly the sebaceous gland also produce sebum, the oil, leading to skin problems like acne and pimple.

Development of hair: there is development of the pubic hair and the hair in armpit

Mental and emotional maturity: an individual gets mental and emotional maturity at this stage. The brain gets developed at this stage and a person has maximum learning power.

Sexual feeling: during adolescence a liking towards opposite sex  develop

Development of sex organs: the pituitary gland release hormone to activate the sex organs such that they can release the gametes. The ovary release ovum and the testes release sperm it start with the development of sex organs.

Secondary sexual character: sexual character develop in human beings

     Changes in male:

·         growth of  beard and moustaches

·         chest gets broad

·         development of pubic hair and hair in armpit

·         development in penis

·         enlargement of voice box

·         muscular development of body

   Changes in female:

·         growth of mammary gland and breast

·         pelvic region broadens

·         hips gets broader

·         development of pubic hair and hair in armpit

rock and types

What is rock?

Rock is a hard solid substance composed of one or more minerals.

Basically there are three types of rocks

1.Igneous rock

2.Sedimentary rock

3.Metamorphic rock

Igneous rock are the condensed lava that come out of the core of earth and cool down on the surface. When the tectonic plates of earth move causing volcano eruption lava come out from the inner core of earth, this molten lava when settles down on the crust and cools down it solidifies to form hard structure called rock

Igneous rock are of two type: basaltic rock (basalt) and granite

Basalt is formed by cooling of the molten lava on the surface of earth. It is a very fine grained rock

Granite is formed when lava from the core looses its force while come out to earth crust, some lava gets trapped along with the crust i.e , lava gets combined with the coarse soil and after cooling it solidifies in the form of a coarse grained rock

Sedimentary rock, these rocks are formed by the deposition of sediments formed by the weathering of other earthly structures. When the deposits from various sources like wind and water settles down on each other, the continuous pressure exerted by the upper layer hardens the layers beneath forming a hard structure. This hard structure is called sedimentary rock

Metamorphic rock, these rocks are formed when sedimentary rocks present inside the layers of earth undergoes changes in the presence of pressure and heat.

hetertotrophic nutrition

Heterotrophic nutrition

Heterotrophic (Gk. Hetero=different; trophe= nourishment) nutrition: this kind of nutrition is followed by all animals , fungi, some prosists, bacteria and nn green plants. These organisms obtain their food from other plants and animals beacuse they have no chlorophyll to trap solar energy and make their own food. Animals showing heterotrophic nutrition are called heterotrophs.

On the basis of nature of food heterotrophic nutrion is of three types:

1.     saprophytic nutrition

2.     parasitic nutrition

3.     holozoic nutrition

saprophytic nutrition is the mode of nutrition in which heterotrophs get their food from dead and decaying organisms

Saprophytic organisms produce digestive enzyme, these enzyme when released on the food material they breaks down to soluble food . this food in soluble form is absorbed. This method leads to the decay and decomposition of organic food material.

 Saprophytes are mainly bacteria and fungi. Yeast, mushrooms and moulds are saprophytic fungi.yeast feed on sugar solution which helps in its growth. Neottia and monotropa are flowering plants which are saprophyte.

Parasitic mode of nutrition is the phenomenon in which an organism(parasite) lives in or on the body of another organism(host). Parasite absorb the food from the body of their host, in thos process they make damage or even kill their host organism. This phenomenom is called parasitism. This mode of nutrition is showed by non-chlorophyllous plant, viruses and some fungi.

In fungi, mycelium go deep in the host tissue and secrete enzyme. The soli food in host body is converted in soluble form and then absorbed abd assimilated by fungal hyphae. For this purpose, tips of hyphae gets rounded and are called haustoria. Some parasitic bacteria cause diseases in plants and animals, these are pathogens.

Total stem parasite: cuscuta

Partial stem parasite: viscum, loranthus

e.g., puccinia (wheat and barberry plant), roundworms,

ectoparasite e.g., bedbug, head louse,

endoparasite e.g., trypanosome, malarial parasite(intracellular parasite)

taenia, ascaris (coelozoic parasite)or blood fluke, filarial worm (histozoic in body tissue)

green species of euglena, e.g., E.viridis, E.gracilis (autotrophic in light but saprophytic in dark). This dual mode is called myxotrophic nutrition.

Holozoic nutrition is the mode in which digestion is always inside the body, either intercellularly or intracellularly.  Organisms can feed on solid food material. The food may be whole plant animal or their part

Photosynthesis : mechanism

Photosynthesis : mechanism

The process of photosynthesis is divided in two phases:

Dark phase (photochemical reaction)

Light phase (chemical reaction)

Light phase: this reaction phase require light therefore also called photochemical reaction.

First the light energy is absorbed by chlorophyll. This takes place in the grana region. The chlorophyll a pigment traps the visible light in form of quanta or photons (energy). When the chlorophyll molecules are exposed to light they gets exited and emits electrons. Photons are the energy packets emitted by light. This energy is inversely proportional to its wavelength, shorter the wavelength of light higher is the energy of photon.

Light energy is converted into chemical energy and splits water molecule into hydrogen and oxygen. emitted electrons are channelled through electron transport chain in chloroplast. The photons absorbed by chlorophyll  then carries out three function:

i.                    Formation of ATP (Adenosine triphosphate) . ATP is the source of energy used during the during the dark phase of photosynthesis. ATP is formed when ADP (Adenosine diphosphate)  joins a phosphate group.

ADT + Phosphate Gr ----------à ATP

ii.                  Photolysis of water. Decomposition of water with the help of light energy  into hydrogen and oxygen is called photolysis of water

Water + energy -------à Hydrogen + oxygen

This oxygen is by product of photo synthesis.

iii.                Synthesis of NADPH (reduced nicotinamide adenine dinucleotide phosphate). Hydrogen ions released from water  joins with NADP and reduces it to NAPH. This is also used in dark reaction.

Dark phase: this is the light independent phase. It does not need light energy and thus it is completely chemical process. This reaction takes place in stroma region of chloroplast

Carbon-dioxide is reduced to carbohydrate. Carbon dioxide is reduced to glucose by hydrogen in NADPH and energy in ATP. This reaction is also called clavin cycle. Melvin clavin explained this process using radioactive carbon.

ATP and NADPH molecules together are called as assimilatory power.

RuBP  + CO₂  + NADPH  + ATP  ------à   RuBP  +  C₆H₁₂O₆    +  ADP  +  NADP  + Po₄

RuBP : ribulose biphosphate enzyme

RuBP combines with  CO₂ to make carbohydrate and regenerating RuBP.

Diagrammatic representation of photosynthesis mechanism.

  

Significance of photosynthesis

1.     Food . food is synthesized from raw material like carbon-dioxide and water.

2.     Oxygen . oxygen required for respiration and combustion processes are formed as a  by-product of photosynthesis.

3.     Fuels. Fossil fuel lie coal, oil natural gas are forms of stored solar energy synthesized by photosynthesis.

PHOTO-AUTOTROPHIC MODE OF NUTRITION

PHOTO-AUTOTROPHIC MODE OF NUTRITION

Photo-autotropic mode of nutrition or photosynthesis  is the process by which photoautotrophs synthesize food in the presence of sunlight, CO₂ and H₂O. by this method solar energy is trapped by autotrophic organism and converted into food. In this process carbohydrates are synthesized from simple inorganic compounds like carbon dioxide and water in presence of chlorophyll and sunlight.

In plants the unused carbohydrates are stored in form of starch.

In animals unused food is stored in form of glycogen.

Chloroplast

Chloroplasts(G.k  chloros- grass green   plastos-moulded) are the green plastids which help in the synthesis of organic food. These are uniformly distributed in cytoplasm of plant cell.  Chloroplast is found in the upper surface of leaf, thus exposing it to maximum sunlight so that more solar enery is absorbed.

It is covered by a double membranous structure called chloroplast envelope where each membranous structure is a unit of plasma membrane like structure. This membrane can be observed by electron microscope.

Protein matrix present in chloroplast is called matrix or stroma.

Lamellae or thylakoids are a membrane system which run parallel to each other in stroma. There are two types of thyllakoids present in higher plants. Large thylakoid (stroma thylakoid)  extend from one end to other end of chloroplast , small thylakoid (grana thylakoid) are disk shaped and closely placed to each other to form grana. Grana and stroma thylakoid fuse with each other in the region of granum

Photosynthetic pigments

These are the pigments involved in photosynthesis. e.g.  chlorophyll, carotenoid (carotenes and xanthophylls) , anthocyanin, phycobilins (phycocyanin and phycoerythrin)

Chlorophylls are green pigment present in chloroplast and gives green color to plants. These are of seven types . chlorophyll a, b, c, d, e, bacteriochlorophyll and bacterioviridin. These traps solar energy and converts it into chemical energy during photosynthesis.

Carotenoids are lipid and are classified in two groups: carotenes which are orange red in color. Xanthophylls are yellow in color.

Carotenoid absorb light energy and transfer it to chlorophyll a and act as accessory pigment.

Site of photosynthesis

Photosynthesis takes place in chloroplast which contain the pigment chlorophyll. These pigments are therefore available in the green part of plants like leaves , green stem.

Carbon dioxide diffuses in the leaf through stomata present in lower surface of leaf. Chloroplast which is present in the upper surface of leaf captures more sunlight.  Leaf vein brings the water .

Raw material needed during phtotosynthesis

1.     Carbon dioxide – forms 0.32 % of total atmosphere. Provides carbon for carbohydrate formation. Hydrophytic plant use CO₂ dissolved in water

2.     Water – provides hydrogen for carbohydrate foemation. Helps in keeping stomata pores open. Deficiency of water  can cause closing of stomata thus checking CO₂  to enter the leaf.

Solar Energy is trapped in chloroplast and converted into chemical energy. This chemical energy is ATP ( adenosine triphosphate).

Carbohydrate synthesis during photosynthesis

6CO₂ + 6H₂O   ---^{light+chlorophyll}----à C₆H₁₂O₆ + 6O₂

Photosynthesis is the process where light energy is converted in chemical energy. Solar energy is captured by chlorophyll in presence of carbon-dioxide and oxygen and carbohydrate (food) and oxygen are formed. this biochemical  activity of plant uses solar energy to make their food, this carbohydrate undergoes respiration to release energy to be used in various metabolic activities.

Contd…

nutrition

                                                                                                            Previous topic: Life process intro

Nutrition is the process of intake of food,its digestion, absorption and distribution to diffrent part of body

Food an organic substance, is used by living beings to remain alive. It is the source of energy and provide raw material for the synthesis of body constituents. When consumed, food passes through biochemical changes and finally the nutrients are absorbed by or body. The main classification of types of food:

Carbohydrate and fat (energy giving)

Protein and mineral salt (body building)

Vitamin and mineral (regulating food)

The simplest form of food is glucose, this does not need and any further breakdown and when consumed gives instant energy.

Mode of nutrition (on the basis of taking of food)

1.       Autotrophic nutrition

2.       Heterotrophic nutrition

Autotrophic nutrition (Gk. Auto-self, troph-nutrition) they use raw material from environment to manufacture their own food. Autotrophs are divided in two category on the basis of the way they manufacture their food

a.       Photo-autotrophic (photosynthesis)

b.      Chemo-autotrophic(chemosynthesis)

A.      photosynthesis is shown by green plants, protists and photosynthetic bacteria. These contain chlorophyll, a green pigment which help them sysnthesize food in presence of simple raw material like CO₂, H₂O in presence of sunlight.

B.      In chemosynthesis energy stored in food is obtained from some chemical, they require only organic material from atmosphere, carbon is obtained from CO₂._.  e.g.; Hydrogen  bacteria, iron bacteria, nitrifying bacteria.
 
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