1-Growth,

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1-Growth, 2-Development and 3-Aging
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GROWTH

• Growth is the increase in size per unit time
  (year). Growth is normally accompanied by
  sequence of maturation changes
• increased protein synthesis
• increased height
• increased body weight
  increased number of
  cells .
• NB growth is not just increased body weight
  

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Growth curve

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Conclusions obtained from the growth curve
1) There are two
periods of rapid growth rates (growth
spurt) A-The first is in infancy it is partly a
continuation of fetal growth period due to the
action of growth hormone. B-The second growth
spurt is at puberty and is due to - growth
hormone - sex hormones (androgen and
estrogen ) . 2) Sex difference in the rate of
growth
-
Girls mature earlier than boys (estrogen is
secreted earlier than testosterone),
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FACTORS AFFECTING GROWTH

• Genetic Factors.
• Relation between height of parents and the
  height of their children.
• 2-Nutritional factors.
  
  Adequate food is essential for normal growth.
  Food must contain adequate caloric supply ( rich
  in proteins of high biological value , vitamins
  and mineral (

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3-Hormonal factors A-Growth hormone (GH)

-Secreted from anterior pituitary
gland -GH stimulates the liver to form insulin -
like growth factor- I (IGF-I) -IGF-I causes
-proliferation ( increased cell division ) of
chondrocytes of epiphyseal cartilage of growing
bones and elongation of these bones
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B-Thyroid hormones (Thyroxine and Tri iodo
thyronine) -Are essential for normal secretion
and functions of growth hormone (permissive
action of growth h.) -Are essential for sexual
development -Are essential for normal brain
development -(ossification of cartilage,
growth of teeth, contour of face and proportion
of the body)
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• B-insulin
• -secreted from endocrine part of the pancreas
• -is essential for increased oxidation of
  glucose, so , preserves ( keeps) amino acids
  for protein synthesis.
• NB Children suffering from decreased insulin
  secretion ( diabetes mellitus ) have slower rate
  of growth than normal children. Lack of insulin
  ------- hyperglycemia --------- inhibition of
  growth h. secreation

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C-Sex hormones -secreted during puberty


Estrogen from the ovary

Testosterone from the testes -
Actions of sex hormones .(1- protein anabolic
effects . 2- stimulate GH secretion )

a-
Initially ( at first ), they cause rapid rate of
proliferation of epiphyseal
cartilage and bone elongation ( prepubertal spurt
of growth ). b- Finally, they terminate bone
growth by closure of epiphyseal cartilage.
Why castrated children
or animals are longer in height? (Patient with
precocious puberty are dwarfed) precocious
puberty Hyperfunction of testes due to tumour
of leydig cell secreting testosterone
(pseudopubertiy if it occurs during childhood)
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D-Cortisol -Normal level of cortisol is
essential for normal growth -Decreased or
increased secretion of cortisol, during the
period of growth, decreases the rate of
growth. 4-Catch - up growth -Following a
disease or starvation (decreased food intake ,
there is a period of catch up growth during
which the rate of growth is greater than normal
and the increased rate of growth continues until
the previous rate of growth is reached -The
mechanism of catch- up growth is not known
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Short stature Causes 1- Cretinism
hypothyrodism in children. 2- Pituitary dwarfism
? GH before puberty. 3- Pituitary infantilism
? GH GTH. 4- Precocious puberty Excessive
secretion of Adrenal sex h. (Androgen). 5-
Turners' syndrome (Gonadal dysgenesis) short
stature rudimentary ovaries due to
abnormal XO chromosome 6- Metabolic Bone
diseases. 7- Familial constitutional dwarfism.
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Cretinism Dwarfism
1-Cause ?Th.H. in children ?GH in children
2-Physical G. A symmetrical retardation Symmetrical retardation
3-Mental Idiot normal
4-Sexual Sterile impotent normal
5-Face Swollen eyelids Depressed nose Enlarged protruded tongue between thick lip Childish
6-Dentition Delayed normal
7-Ossification Delayed normal
8-Skin Dray and coarse smooth
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PUBERTY
- Definition The period of life during which
sexual and physical maturation occur in boys
and girls . (onset of adult sexual life)Puberty
occurs when there is maturation of the
hypothalamo -hypophysial - gonadal axis. AGE
OF ONSET OF PUBERTY The age at which puberty
occurs is variable. In the USA, puberty generally
appears between - 8-13 years for girls. -
9-14 years for boys .
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The timing of puberty is variable and depends on

1- Genetic factor( major
role )

2- Other factors including


- Geographic location.

- Light(solar rays).


- Health.
- Nutritional state.


- Body fat composition.

- Psychological
factors.
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• TERMS OF PUBERTY
• 1-Adrenarche
  
  
  onset of adrenal androgen production
  ------signals to onset of puberty.
• precedes puberty by 2-3 years age 7-8.
• 2- Thelarche
  
  
  Onset of breast bud development -
  an estrogen induced effect. Average - 10.8 years
  USA.
• 3- Pubarche
  
  
  Onset of pubic hair growth under influence of
  estrogen or testosterone. Age-11.0 in females
  11.6 in males .
• 4- Menarche
  
  
  Onset of menstrual flow.
  Average age is 12.8 years in the USA.

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MECHANISM Puberty is due to maturation of
hypothalamic pituitary- gonadal axis - The
hypothalamus stars secretion of gonadotropin
releasing hormone (GnRH )
-anterior pituitary gland responds to GnRH
by releasing FSH and LH -gonads ( ovary and
testes) respond to FSH and LH by sex hormones
produce external characters of puberty
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Girls Boys
Gametogenesis Ova Sperms
Secretion of hormones Estrogen and progesterone Testosterone
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• MECHANISM OF ONSET OF PUBERTY
• In children, it has been found that
• Hypothalamus contains GnRH
• Anterior pituitary gland contains FSH and LH
• Gonads can respond to FSH and LH
  
  BUT..
• The hypothalamus does not release GnRH till the
  time of puberty. This can be explained by
• 1 During the period from birth to puberty,
  a neural mechanism is operating to
  prevent the normal pulsatile release of GnRH.
• When this neural mechanism is inhibited,
  pulsatile release of GnRH start

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2 Nutritional theory regarding puberty
Weight
gain and percent of body fat is prerequisite
(important) to puberty
(48kg and 17 fat). This is because fat cells
secrete leptin
Leptin hormone secreted from fat cells into the
blood leptin secretion is related to the onset of
GnRH secretion
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CHANGES WHICH OCCUR DURING PUBERTY
Boys Girls
1-Stage one No sexual development No sexual development
2-Stage two Testes enlarge -Breast budding -first pubic hair -height spurt( increase )
3-Stage three penis enlarges - pubic hair starts to grow - ejaculation ( wet dreams) - breasts enlarge - pubic hair darkens and become curled - vaginal discharge
4- stage four testes and penis continue to enlarge - pubic hair becomes curled - height spurt( increase) - male breast development - onset of menstruation - nipple is distinct from the areola
5- stage five fully mature male - pubic hair extends to inner thighs - increase in height slows then stops - fully mature female - pubic hair extends to inner thighs - increase in height slows then stops
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Abnormal 1-precocious psodopubertypuberty Early
Development of secondary sex character without
gametogenesis ( no spermatogenesis or
oogenesis) Causes abnormal over secretion of sex
h. by adrenal cortex or gonadal tumors


over secretion of sex h .-------inhibition of Gn
H------------inhibition of gametogenesis . 2-true
precocious puberty (early puberty with
gametogenesis) Cause release of hypothalamic
GnRH DUE TO Hypothalamic disease (interruption
of inhibitory neural pathway)
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chronic stimulation of GnRH by irritative
focus 3-delayed puberty Puberty failed to occur
by the age of 17 year in females and 20 year in
males. Causes panhypopituitarism,
hypothyroidism .
Hair distribution in male and female
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• Male Reproductive system
• Male reproductive system is formed of
• 1 Primary sex organ (Testis)
• 2 Duct system
• epididymis
• prostate
• seminal vesicles
• vas deference
• Cowper, s gland ( bulbo uretheral glands )
• penis and scrotum

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TESTES Is formed of


a Seminiferous tubules containing two types
of cells
i- germ cells (
spermatogonia) which continuously divide to
form SPERM
ii-Sertoli cells which support , give nutrition
to the dividing germ CELLS
b Interstitial cells (Leydig cells) which
secrete testosterone into the blood
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FUNCTIONS OF THE TESTES
-1-Gametogenesis
Spermatogonia (46 chromosomes) continuously
divide to form mature spermatozoa(23
chromosomes) 2- Endocrine functions Leydig cells
secrete testosterone hormone into the blood
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• Functions of testosterone (Androgens)
• Testis secretes testosterone which reaches the
  target cells where
• testosterone acts directly on the target cells
• testosterone is changed to dihydrotestosterone
  (DHT) by the action of 5- a reductase enzyme
• Actions of testosterone and dihydrotestosterone
• 1 During intra uterine life
• 2 From birth till pre - pubertal life
• 3 At and after puberty

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• 1 Actions of testosterone during intra uterine
  life
• During intra uterine life, primitive reproductive
  system is similar in male and female embryos. The
  primitive reproductive system is formed of
• A - Gonad
• B - Duct system formed of
• Wollfian ducts (male duct)
• Mullerian ducts (female duct)
• C Urogenitial sinus

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Male Female
Primitive gonads Under the effect of sex determining region of the Y chromosome (SRY), primitive gonad is changed into Testes secretes Testosterone from Leydig cells Mullerian inhibitory substance from Sertoli cells Develops into ovaries in absence of Y chromosome
Wollfian ducts Testosterone stimulates the development of Wollfian duct into Epididymis Vas deferens Seminal vesicles Ejaculatory ducts Regress
Mullerian ducts Mullerian inhibitory substance causes regression of Mullerian ducts Develop into Uterus Fallopian tubes
Urogenitial sinus Testosterone is changed into dihydrotestosterone (DHT) by 5 a reductase enzyme DHT stimulates the development of urogenitial sinus into Prostate Urethra Penis Scrotum Develops into Vagina External genitalia Clitoris Labia majora Labia minora
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2 Actions of testosterone from birth till pre -
pubertal life
After birth, testosterone level decreases and the
starts to increase at time of puberty.
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)
3 Actins of testosterone at and after
puberty Testosterone and dihydrotestosterone
(DHT) are responsible for body changes at puberty
in boys (male secondary sex characters)
External genitalia Increased length and size of the penis Scrotum becomes pigmented and rugose
Internal genitalia Seminal vesicles Enlarge Secrete fructose Prostate and bulbourethral glands Enlarge and secrete
Voice Larynx enlarge Vocal cords increase in length and thickness Voice becomes deeper
Hair growth Hair growth Beard appears Hair line on the scalp recedes antero laterally Pubic hair grow with male pattern (triangular with apex up) Hair appears in axilla chest General body hairs increases
Mental More aggressive Active attitude Interest to opposite sex develops
Body configuration Shoulder broaden Muscles enlarge
Skin Sebaceous glands secretion increases and becomes thicker. This predispose to acne
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Testosterone stimulate baldness in males
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• Mode of action of testosreone
• Testosreone binds to an intracellular receptor
• Receptor steroid complex then binds to DNA in
  the nucleus, stimulating the transcription of
  various genes
• In addition, testosterone is converted to
  dihydrotestosterone (DHT) by 5a reductase in
  some target cells. DHT binds to the same
  intracellular receptor as testosterone.DHT also
  circulate in the plasma with a plasma level 10
  that of testosterone

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Testosterone Dihydrotestosterone
Hormone receptor complex in target cells Less stable More stable
Conform (fit)to DNA binding state Less More
Actions During intra uterine life Testosterone stimulates the development of Wollfian ducts into Epididymis Vas deferens Seminal vesicles Ejaculatory ducts During pubertyTestosterone Increases muscle mass Sex drive and libido Spermatogenesis Gonadotropin (FSH and LH) regulation During intra uterine life Dihydrotestosterone stimulates the development of urogenitial sinus into Prostate Urethra Penis Scrotum During puberty Dihydrotestosterone causes Enlargement of prostate and penis at puberty Development of facial hair Temporal recession of hair line Acne formation in the kin
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Two types of 5-a reductase are expressed by two
different genes Type 1 5-a reductase is
present in the skin throughout the body and in
the scalp Type 2 5-a reductase is present
in genital skin, the prostate, and other genital
tissues
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Hormonal control of testosterone secretion

• At time of puberty
  
  1) The hypothalamus
  secretes gonadotropin releasing hormone (GnRH)
• 2) GnRH reaches the anterior pituitary gland to
  stimulate the secretion of FSH and LH
• LH acts stimulates the Leydig cells to secrete
  testosterone
• FSH and testosterone act on germ cells and
  Sertoli cells to stimulate germ cell division and
  spermatogenesis and finally sperm formation
• 3) Negative feedback control
• Sertoli cells secrete inhibin hormone which
  inhibits the secretion of FSH
• Leydig cells secrete testosterone which inhibits
  LH secretion

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FUNCTIONS OF MALE DUCT SUSTEM
Epididymis Is responsible for final maturation of sperms
Vas deference Transports sperms from epididymis
Seminal vesicles Secrete fructose into seminal fluid( fructose is nutrient for sperms)
Prostate Secretion of the following into seminal fluid i- alkaline fluid ii- citric acid iii- calcium ions iv- coagulation proteins
Bulbo-uretheral glands Secretion of mucus into the urethra during sexual act
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Female Reproductive system Female reproductive
system is formed of 1- Primary sex organs
(ovaries)2- Secondary sex organs (duct system)
a- Fallopian tubes. b-Uterus. c-Vagina.
d-External genitalia. - Labia majora.
- Labia minora. - Clitoris .
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• Functions of the ovary1- Formation of mature
  ova2- Secretion of female sex hormones
• Estrogen
• progesterone
• Ovarian cycles
• The ovary shows monthly cyclic changes called
  ovarian cycles These cyclic changes are caused by
  interplay (interaction) between
• 1-Hypothalamus and anterior pituitary gland
  cyclic changes a-hypothalamus secretes
  gonadotropin releasing hormone (GnRH)
  b- GnRH stimulates the anterior pituitary to
  secrete FSH and LH c- FSH and LH act on the
  ovary
• 2-Ovarian cyclic changes
• Monthly production of mature ovum
• Monthly cyclic changes in the secretion of
  estrogen and progesterone

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Mechanisms of ovarian cycle
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I-Follicular phase By the onset of puberty 1)
Anterior pituitary gland secretes large amount of
FSH and smaller amount of LH2) FSH and LH cause
growth and development of many ovarian follicles.
These growing follicles secrete estrogen
which inhibits the secretion of FSH and LH
(negative feedback)3) One of these
follicles continues to grow and develop while the
other follicles degenerate ( die)4) The
follicle that continues to grow forms the mature
Graafian follicle which secretes large
amount of estrogen which stimulates the
hypothalamus to release pulses of GnRH
(positive feedback ) which occurs 36 hours before
ovulation5- GnRH stimulates the anterior
pituitary gland to secrete large amount of LH (LH
surge) and small amount of FSH6-Estrogen causes
proliferative changes in the endometrium NB
follicular phase lasts from 5 th day to the 14 th
day of 28 days cycle
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• II - Ovulation
• Onset
• Ovulation occurs at the 14 th day of 28 days
  cycle
• The duration of the cycle may be more or less
  than 28 days but the time of ovulation is fixed
  and is 14 days before the onset of the next cycle
  (next menstruation)
• Hormone responsible
• Ovulation is caused by LH which increases
  markedly at the mid cycle
  
• Under the effect of LH, the Graafian follicle
• reaches full maturation
• ruptures
• releases the ovum into the peritoneal cavity and
  the ovum ispicked up by the fallopian tube

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• III-Luteal phase
• Under the effect of LH , empty Graafian follicle
  is changed into corpus luteum
• Corpus luteum secretes progesterone and estrogen
• Progesterone causes secretory changes in the
  endometrium . progesterone causes negative
  feedback inhibition of LH
• At the end of Luteal phase, the corpus luteum
  degenerates ( due to decreased LH ) causing
• drop of progesterone and estrogen secretion which
  causes
• necrosis of the endometrium which causes
• menstruation
• Next cycle starts as followsDrop of progesterone
  and estrogen secretion which causes increased FSH
  and LH . FSH and LH cause Growth and maturation
  of many follicles and ovarian cycle proceeds

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• Endocrine Functions of the ovary
• The ovary secretes two hormones 1- Estrogen
  2-Progestrone
• 1- Estrogen
• Sites of secretion Estrogen is secreted from
  the ovary
• during follicular phase from the growing
  follicles and mature Graafian follicle
• during the leutal phase from the corpus leutum
  
• Functions
• estrogen is essential for growth and maturation
  of the ova by direct action on the growing
  follicles
• estrogen is essential for development of
  secondary sex organs (uterus, Fallopian tubes,
  cervix, vagina, and external genitalia) during
  puberty
• Estrogen is essential for development of
  secondary sex characters (breast, hair, skin,
  mode and behavior).

NB The growth of the clitoris is controlled by adrenal androgens
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• 2- Progesterone
• Sites of secretion Progesterone is secreted
  from the corpus leutum during leutal phase
• Functions
• prepares the uterus for implantation of
  fertilized ovum
• progesterone is essential for maintenance of
  pregnancy by causing
• relaxation of uterine muscles
• secretory changes in the endometrium

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• Menstrual (endometrial or uterine) cycle
• The endometrium of the uterus shows cyclic
  changes. These cyclic changes are caused by
  cyclic changes in the ovarian hormones
• First
• Ovary secretes estrogen from the growing
  follicles and mature Graafian follicle
• Estrogen causes proliferation ( increased cell
  division and endometrial thickness 3-4 ml,
  uterine glands enlarged, spiral arteries
  developed and stromal cells increase in number)
• Second
• After ovulation, the ovary secretes progesterone
  and estrogen from the corpus leutum
• Progesterone causes secretory changes in the
  endometrium (endometrial thickness 5-6 ml,
  highly vascularised and edematous - uterine
  glands become coiled, tortuous and start their
  secretion- spiral arteries become more
  tortuous-lipids and glycogen deposits in stromal
  cells)
• Finally
• The corpus leutum degenerates. This causes drop
  (marked decrease) of progesterone and estrogen
  levels in the blood.
• This causes necrosis (death) of the endometrium.
• This is followed by shedding (separation) of
  necrosed endometrial and bleeding (menstruation
  )

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Menstrual cycle is divided into 1
Proliferative Phase From the 5 th day to the 14
th day Ovary secretes estrogen from the growing
follicles and Graafian follicle Estrogen
causesproliferation and increased thickness of
the endometrium 2 Secretory phase From the 14
th day to the 28 th day Ovary secretes
progesterone and estrogen from the corpus leutum
Progesterone causessecretory changes in the
endometrium
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3 Destructive phase (menstrual
bleeding or menstruation from day 1 ( onset of
menstruation) to the 5 th day. Corpus leutum
degenerates and the blood levels of progesterone
and estrogen drops markedly. Drop of
progesterone and estrogen levels cause
necrosis ( death ) of the superficial
endometrium followed by shedding of the
necrotic endometrium and menstrual bleeding
Menstruation average duration 3- 5 days average
amount ranges from slight spotting to 80 ml blood

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Aging Aging is a complex biological process in
which changes at molecular, cellular and organ
levels result in a progressive decrease in the
body's ability to respond appropriately to
internal and/or external stressors THEORIES ON
THE CAUSE OF AGING One must remember the
difference between the cause and the effect of
aging. While the following theories may explain
the causes of aging, they may be , simply , an
effect of the aging process Theories that
explain the causes of aging cab be separated into
two groups
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Old and aging depends on the age and experience
of the speaker. --Chronological age - number of
years lived --Physiologic age - age by( body
function systems) --Functional age - ability to
contribute to society
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CHRONOLOGICAL CATEGORIES
Young-Old - (ages 65 - 74) Middle-Old - (ages 75
- 84) Old-Old - (age 85 and older)
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Characteristics --Poor mental and physical
health --Low socioeconomic status --Predominantly
female --Possibly isolated living
conditions --More and longer hospital stays,
and --More money spent on health care and drugs
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I DNA Damage Theories
Aging is caused by accumulated damage to DNA,
which in turn, inhibits the cell ability to
function and express the proper genes. This leads
to cell death and aging process

1- DNA Damaging /
Repair Theory 2- Free Radical / Oxidation Theory
3- Radiation Theory
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II Built In Breakdown Theories
1- Telomere Theory 2- Genetic Theory
3-Immunological Theory DNA controls the
formation of proteins needed to maintain life
RNA Transfers information from DNA to
the ribosomes where proteins are formed
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I DNA Damage Theories I DNA Damage Theories
1-DNA Damage/Repair Theory  
DNA damage occurs continuously in the living
cells. While most of these damages are repaired
(by DNA polymerase and other repair mechanisms),
these repair mechanisms cannot correct the damage
as fast as damage occurs, so, DNA damage
accumulates inside the cells and interferes with
RNA transcription It has been suggested that the
decrease in ability of DNA to act as a template
for gene expression is the primary cause of aging
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2-Free Radicals Theory Free radicals is any
molecule with one or more unpaired electrons in
its outer shell

Important free radicals

superoxide ions ( O2- )
hydroxyl radicals ( OH- )
singlet oxygen ( 0- ) hydrogen
peroxide (H2O2 )


Sources of free Radicals

1 free radicals cannot be avoided because
they are products of biochemical
reactions in the body ( in mitochondria )

NB NO FIRE( in
mitochondria)WITHOUT SMOKE( free radicals )
2 free radicals
are also found in the environment and result from
air pollution,
tobacco smoke, radiation, and toxic wastes
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Effects of free radicals
1-Breakdown of cell membrane lipids (
lipid per oxidation )
2- breakdown of nuclear
membrane , so , exposing the genetic material in
the nucleus ( DNA )

- DNA is
sensitive to free radicals induced damage

- free radicals cause damage of DNA and
eventually cell death3- disturb the function s
of immune system
All these
are known as oxidative stress .All of which
contribute ( share ) to the effect of
aging


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Anti oxidants (free radicals scavengers)

-substances that neutralize free radicals by
supplying them with extra electron, so,
decreasing the activity of free radicals but
these antioxidants are left with unpaired
electron -The structure of the antioxidants with
unpaired electron is not damaging to the body
cells -Anti oxidants include vitamin C,
vitamin E, and vitamin A
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NB Caloric Restriction Caloric restriction has
been found to decrease free radicals production
and to increase the life span of rodents (as
rats)
Studies have shown that both caloric restriction
and reduced meal frequency / intermittent
fasting decrease the development of various
diseases and can increase life span in rodents
by 30- 40 by decreasing oxidative stress. BUT
Severe caloric restriction over 50 will result
in increased mortality
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3-Radiation Theory This theory focuses mainly on
aging of the skin cells because skin cells are
the most directly affected cells by external
sources of radiation. The shorter more energetic
spectrum of ultraviolet rays (ultraviolet ) is
responsible for dermal connective tissue
destruction observed in aged skin cells Effects
of radiation

Radiation can generate free
radicals as radiation strikes water molecules in
the skin. Free radicals, in turn, cause cell
death
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II Built In Breakdown Theories II Built In Breakdown Theories
1-Telomere Theory  
Telomere are caps on the ends of chromosomes
With each cell division , the telomeres are
shortened Functions of telomeres 1- allow
complete replication( doubling) of chromosomes
2- protect chromosomal ends from recombination
sowhen the telomeres become too short ,
their function is disturbed and cells stop
division It has been observed that cells with
shorter telomeres undergo limited number of
divisions than those with longer telomeres
ACCORDINGLY.

Telomeric length is a
biomarker of somatic cell aging in humans and
when the telomere becomes too short, the cells
stop division and dies off
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Telomerase Enzyme responsible for restoring
(re-forming) the lost telomeres in the
chromosomes, as a result, the cells can divide
for infinity Telomerase enzyme is present
in 1- germ cells (continuously dividing
cells) 2- telomerase enzyme is activated
in cancer cells
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2-Genetic Theory Experiments have demonstrated
that i- human cells can divide less than 100
times outside the body ii- there is an inverse
relation between the number of cell divisions and
the age of the person from which the cells were
taken . Genetic theory states that cell (
aging) is active process and the senescent ( aged
) cell express substances---------- that inhibit
DNA synthesis. Thus, this theory suggests that
aging is predetermined in the genome and that it
is a dominant condition
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3-Immunological Theory The immune system protects
the body from invading microorganisms and mutant
cells that form inside the body . The immune
system acts by two ways a- production
of antibodies that react with invading proteins
of microorganisms b- forming
cells that destroy invading cells
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The peak (maximum) activity of immune system
occurs during adulthood and then
gradually decreases with age. This decrease in
the activity of immune system will lead
to i- increased susceptibility to
infection ii- inability to destroy mutant
cells
iii- inability to
differentiate between self and non self antigens
This will lead to, by the advance of age,
cellular stress and damage and eventually
cellular death.
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NEURO-AGING THEORY
All cells undergo nervous system
degeneration Results in changes in hormonal
release Leads to decline in cell function
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CHANGESO CCURING DURING AGING Aging is different
from person to person. Within the same
individual, organs and tissues age differently.
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• Heart
• Heart tissue thickens with age.
• . Heart smaller and less elastic with age
• By age 70 cardiac output reduced 70
• Heart valves become sclerotic
• Heart muscle more irritable
• More arrhythmias
• Arteries more rigid
• Veins dilate
• Arteries
• Arteries stiffen with age( atherosclerosis)
• Moving the blood through the inelastic arteries
  requires the heart to pump blood with more
  force
• Arterial blood pressure increases (hypertension)
• .

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• Lungs
• Maximum breathing declines 40 between ages of 20
  and 70

-Lungs become more rigid -Pulmonary function
decreases -Number and size of alveoli
decreases -Vital capacity declines -Reduction in
respiratory volume -Bony changes in chest cavity
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• VISION
• The lens tends to opaque (cataract).
• The lens tends to lose elasticity which decreases
  the ability to see near object
• There is a decrease in light and dark
  adaptation.

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• Hearing
• Hair cells tend to be lost in the organ of Corti
• Cochlear neurons tend to be lost.
• Stiffening, thickening, and calcification occur
  in multiple components of the auditory
  apparatus.
• Hearing is impaired ( decreased )

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• RENAL
• General decline in glomerular filtration rate
• Progressive decline in ability to excrete a
  concentrated or a dilute urine
• Delayed or slowed response to sodium deprivation
  or a sodium load
• Delayed or sluggish response to an acid load
• Enlargement of prostate in old male leading to
  retention of urine
• BRAIN
• Age decreases the number of axons that connect
  neurons, as a result neurons dont function
  properly, but their numbers dont decline.
• --Neurons of central and peripheral nervous
  system degenerate
• --Nerve transmission slows
• --Hypothalamus less effective in regulating body
  temperature
• -- decreased deep sleep

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• MUSCULO SKELETAL (Skeletal muscles and Bones)
• skeletal muscles show weakness, atrophy and loss
  of power
• bones become weak and fragile ( osteoporosis) and
  pathological fractures are common especially
  fracture neck of the femur
• 
  Changes in the skeletal muscles and bones are
  due to
• Low dietary intake of Calcium
• Loss of endocrine protection( testosterone in
  male and estrogen in females)
• Reduced endogenous production of Vitamin D
• Disuse
• Disease Chronic Renal Disease, Rheumatoid
  Arthritis, Thyroid
• Drugs (medications as Steroids and Thyroxin)

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Pathological fracture is very common in old age
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• DIGESTIVE SYSTEM
• Stomach
• -Motility reduced
• -pH increased ( decreased HCl secretion)
• Small Intestine Absorption decreases
• Large Intestine Motility reduced (
  constipation is common)
• Liver
• -Blood flow reduced
• -Bile secretion decreases
• SKIN
• Becomes dry, wrinkled with increased
  pigments

86
ENDOCRINE SYSTEM
Decreased ability to tolerate stress - best seen
in glucose metabolism. Estrogen levels decrease
in women Other hormonal decreases include
testosterone, aldosterone , cortisol ,
progesterone
87
IMMUNE SYSTEM
--Decline in immune function Trouble
differentiating between self and non-self - more
auto-immune problems --Decreases antibody
response Fatty marrow replaced red marrow Vitamin
B12 absorption might decrease -- decreased
hemoglobin and hematocrit
Decreased ability to resist invading
microorganisms causing increased liability for
infection
88
REPRODUCTIVE SYSTEM
Female -Declining estrogen and progesterone
levels -Ovulation ceases -Introitus constricts
and loses elasticity -Vagina atrophies - shorter
and dried -Uterus shrinks -Breasts pendulous and
lose elasticity
89
REPRODUCTIVE SYSTEM
Male -Reduced testosterone level -Testes atrophy
and soften -Decrease in sperm production -Seminal
fluid decreases and more viscous -Erections take
more time -Refractory period after ejaculation
may lengthen to days