🧬

BIOLOGY 2
Created @July 3, 2024 10:26 AM

Tags BIO 11.12

Course @July 3, 2024 10:26 AM

HORMONES: ENDOCRINE SYSTEM

RELEASING INHIBITING
HORMONE NAME BENEFITS DISADVANTAGES
FACTORS FACTORS

1. stimulates cell
growth and cell 1.deficiency results in
Growth
Growth hormone division 2. DWARFISM 2. Over secretion
hormone Hypothalamic
Somatotrophic stimulates uptake leads to GIGANTISM 3. Over
releasing somatostatin
hormone of amino acids 3. secretion in adult life causes
factor[GH]
increases rate of ACROMEGALY
protein synthesis

Anterior
pituitary

1. regulates
endocrine function
of thyroid gland 2. 1. Over secretion causes
Thyrotrophin
‘’MASTER Thyroid stimulating increases the HYPERTHYROIDISM 2. Under
releasing
GLAND’’ hormone[TSH] number of cells secretion causes
factor[TRF]
and secretory HYPOTHYROIDISM
activity of cells of
thyroid gland

6 HORMONES

Corticotrophic
releasing 1. Acts on Adrenal
factor[crf] - cortex 2.
Controlled by stimulates the
Adrenocorticotrophic
steroid level in secretion of
hormone [ACTH]
blood 2. or by corticosteroids[
Direct nervous cortisone and
stimulation of aldosterone]
hypothalamus

- Stimula
spermat
GnRH . by stimu
FSH FOLLICLE
Gonadotropin- Sertoli c
GON STIMULATING
releasing complete
HORMONE
hormone developm
spermat
sperms

RE

ADOTROPI LH LUTEINISING GnRH PRODUCTIV ICSH stim

C HORMONE . . leydig ce

BIOLOGY 2 1
 INTERSTITIAL CELL release
STIMULATING testoster
HORMONE IN MALE developm
germina
epitheliu
have spe

promote
producti
(lactatio
mammal
childbirt
Prolactin .
PIF Prolactin plays a r
HORMONE Leuteotrophic SYS
inhibiting factor regulatin
hormone
immune
and
developm
the mam
glands.

MEDIAN
PITUITARY

- increases in
humans during
thin layer of
pregnancy - -
cells b/w
MSH Melanocyte MSH Inhibitory stimulates
anterior and
stimulating hormone hormone production and
posterior
release of melanin
pituitary
by melanocytes in
skin and hair

not very
prominent in
humans

posterior
pituitary

-Undersecretion causes
DIABETES - release
Released by
stores primary ADH Anti diuretic INSPIDUS[Exccessive dehydra
nerve impulses
hormones from hormone - - production of urine and decreas
by
hypothalamus Vasopressin frequent thrist] - - volume -
hypothalamus
oversecretion causes kidney blood pr
problems

Oxytocin Released in waves Over secretion leads to Child bir

during birth for ruptured uterine wall — Under nursing w
labour secretion causes inhibits in lactati
contractions normal labour process women s
does tha
feeding
dilation o
ducts of
mammar

BIOLOGY 2 2
 promotin
ejection

************ ************ ********* ************* *************** ******** *******

THYROID
GLAND

Iodine co
T3 Tri iodothyronine hormone
atoms

Promote basal
metabolic rate 2.
Enhance glucose
catabolism 3.
Enhance the
synthesis of
cholesterol in liver
4. Promote
lower to larynx development of
Thyroid
Two lobes on the nervous sytem Over secretion OF T3 and T4
stimulating
each side of in foetus and causes GRAVES DISEASE
hormone
trachea infants 5.Act on
muscles for their
development and
functioning 6
promote growth
and maturation of
skeleton 7. also
promote normal
motility of GIT

T4 Tetra Iodine co
iodothyronine - hormone
thyroxine Iodine at

increases
deposition of Ca in
bone matrix
Excessive Ca if not deposited in bones high more im
inhibits absorption
2+level in Declining Ca level in blood disturbs muscle in childh
CALCITONIN by the intestine
blood 2+inhibits it function - and may lead to when bo
decreases
stimulates it kidney stones need Ca
reabsorption by
kidney tubules for
its release in urine

FURTHER DETAILS

CALCITONIN ANTAGONISTIC TO PARATHORMONE

PARATHYROID
GLANDS

4 in number

1 hormone

LOCATED ON PARATHORMONE Released when high Ca2+ Controls CALCIUM Oversecretion means u have
THE TYROID Ca2+level low level BALANCE in parathyroid gland tumor -
GLAND in blood BLOOD - Bones soften nervous sytem
Activation of depressed weakness of
vitamin D to muscles kidney stones - - -
absorb Calcium in HYPOCALCEMIA increased
diet Calcium from

BIOLOGY 2 3
 bones by bone excitability of neurons -
resorption Tetany

DETAILS BELOW

small, light
colored masses
stick out from
posterior
surface of
thyroid gland

PANCREAS

Low blood
glucose level -
Stimulated by high insulin
endocrine and increase blood
Glucagon sympathetic level
exocrine glucose level
nervous somatostatin
system -
ALPHA CELLS

ANTAGONISTIC TO ONE ANOTHER

- reduces overall
glucose level in
blood -increases
rate of glucose
uptake by cells e.g
endocrine
fat cells and
tissues in form -DIABETES
skeletal cells,
of patches high blood MELLITUS[undersecretion] - -
muscles -
throughout glucose level - - Over secretion means
Insulin promotes
pancreas… - - ALPHA utilization of glucose is too
glucogenesis -
known as CELLS great and leads to disturbed
increase usage of
‘’ISLETS OF muscle and nerve functioning
glucose in cellular
LANGERHANS’’
respiration and
other body
processes -
inhibits
gluconeogenesis

ADRENAL
GLANDS

Stimulator of
metabolic
activities -
bronchial dilation
Epinephrine
to increase oxygen
flow - increased
blood flow to
muscles

One on each PRODUCED BY stress BOTH SHOW Oversecretion means

kidney MEDULLA… response - SYNERGISTIC aggressive behaviour in
sympathetic EFFECT routine life
nervous ——————————————-
system Undersecretion means failure

BIOLOGY 2 4
 to combat with emergency
situations

influence on
peripheral
Norepinephrine vasoconstriction
—————————
Rise in BP

2 portions
cortex and
medulla

Glucocorticoids
———————
Cortisone

mineralocorticoids

DWARFISM
-Development is much slower
-Individual has short stature

-body parts stay in proportion

-brain development is unaffected

GIGANTISM

Oversecretion of GH in childhood

person still capable of growth

person increases in height abnormally

ACROMEGALY

Bones no longer capable to increasee in length

bones become very thick

hands feet skull nose and jawbone size become big

Nervous stimulation of the hypothalamus for CRF release?

By stress e.g cold heat, pain, fright and infections

HYPERTHYROIDISM

Excess of thyroxin, T3

HYPOTHYROIDISM

lack of thyroxin

ADULTS HYPOTHYROIDISM aka MYXEDEMA

1. Deficiency of iodine in diet

puffy eyes

Low metabolic rate

BIOLOGY 2 5
 feeling chilled

thick, dry skin

hair lost from scalp, eyebrows

tongue swelling

constipation

enlarged thyroid gland..goiter

OEDEMA [swelling of foot legs ankles, by fluid filling happens due to same position while sitting or standing]

Congenital hypothyroidism aka CRETINISM

severe in infants

mental retardation

poor physical growth

disproportionate body size

bone maturation very delayed

puberty severely delayed

infertility very common

GRAVES DISEASE
Oversecretion of T3, T4

Diabetes insipidus (DI)

is a condition where the body has an imbalance of water due to issues with antidiuretic hormone (ADH or vasopressin).
In central DI, the body doesn't produce enough ADH, often due to damage to the hypothalamus or pituitary gland. In
nephrogenic DI, the kidneys don't respond properly to ADH, potentially due to genetic factors, kidney disorders, or
certain medications. Symptoms include excessive thirst and the excretion of large amounts of diluted urine, leading to a
risk of dehydration.

DIABETES MELLITUS

High blood,urine glucose level

The fibers of neurosecretory cells refer to the axons and dendrites of these cells.

In your book, it is written that LH (Luteinising Hormone) stimulates Leydig cells to release testosterone because, in
many contexts, LH is used as a general term for both males and females. While it is correct that LH is also referred to as
Interstitial Cell Stimulating Hormone (ICSH) in males, the use of LH is often preferred for simplicity and consistency
across both genders.

Therefore, both statements are correct:

LH (or ICSH in males) stimulates Leydig cells to release testosterone.

Vitamin D Activation:Role of PTH: PTH stimulates the conversion of vitamin D into its active form, calcitriol (1,25-
dihydroxyvitamin D) in the kidneys.Function of Calcitriol: The active form of vitamin D increases calcium absorption
from the gut. This ensures that more dietary calcium enters the bloodstream.Importance: Without sufficient active
vitamin D, the body cannot absorb calcium efficiently from the diet, leading to lower blood calcium levels despite
adequate dietary intake.

1. Discuss the role of Sertoli cells.

They r elongated cells found in seminiferous tubules of testes

Complete development of sperms from spermatids when stimulated by FSH

BIOLOGY 2 6
 They nourish the spermatids

Sertoli cells produce Inhibin hormone to control spermatogenesis at a normal rate.

2. WHAT’S THE ROLE OF LH IN MALE HORMONAL REGULATION?

LH or more specifically ICST in males stimulates the leydig cells to release TESTOSTERONE

Testosterone causes growth and development of germinal epithelium to form sperm

Elevated calcium levels in the blood, or hypercalcemia, can lead to several serious health issues. Muscle weakness and
difficulty in movement occur because calcium stabilizes the muscle cell membranes, making them less excitable and
leading to reduced muscle strength and quicker fatigue. Neurologically, high calcium levels decrease neural excitability,
causing diminished reflexes, cognitive impairments, and sensations of numbness or tingling. Cardiovascularly, it can cause
bradycardia and arrhythmias due to disrupted electrical signaling in the heart. High calcium also contributes to the
formation of kidney stones, causing severe pain and potential kidney damage. Additionally, calcium leaching from bones
can weaken them, increasing the risk of fractures. Effective management through hydration, medications, dietary
adjustments, and regular medical monitoring is essential to mitigate these risks.

In hypocalcemia, where calcium levels in the blood are low, there's an increase in neuronal excitability due to changes in
ion channels. This heightened excitability can lead to tetany, a condition where muscles remain in a contracted state
involuntarily. Neurons become more sensitive to stimulation, resulting in frequent and prolonged action potentials. This
excessive nerve activity causes muscles to contract uncontrollably and can lead to muscle spasms, cramps, and in severe
cases, sustained contractions that affect movement and posture. Treatment involves addressing the underlying cause of
low calcium levels, such as vitamin D deficiency or parathyroid gland dysfunction, and restoring calcium balance through
supplements or other medical interventions to prevent neurological and muscular complications.

BIOLOGY 2 7