Science Reviewer

3rd Quarterly
Endocrine System
a. Glands and hormone secretions
b. Functions of hormones
c. Effects on the human body of high and low levels of Hormones
 GLAND HORMONE FUNCTION

A Pineal Gland Melatonin → Regulation of sleep and circadian

rhythms

B Hypothalamus Oxytocin → Controls muscle contraction in the

uterus and milk production
ADH
→ Increases water uptake in the kidney
C Pituitary Gland Adrenocorticotropic → Stimulates adrenal gland to produce
Hormone (ACTH) specific hormone
Thyroid Stimulating
Hormone (TSH) → Stimulates the thyroid gland to
produce thyroxine
Human Growth
Hormone (HGH) → Regulates growth
Proctatin → Milk production and the development
of mammary glands within breast tissues

D Thyroid Gland Thyroxine → Regulates iodine level in the

bloodstream
Calcitonin → Regulate calcium levels in our body
E Parathyroid Gland Parathyroid Hormone → Regulates minerals – calcium and
(PTH) phosphorus in the bloodstream

F Thymus Thymosin → Stimulates the development of

disease-fighting T-lymphocytes or T cells

G Adrenal Gland Adrenaline → To prepare the body for ‘fight or flight’

H Pancreas Insulin → Produced by the pancreas which
regulates blood sugar levels
Glucagon → Stimulates the liver to convert the
glycogen to glucose

I Ovary Estrogen → Controls female sex drive & secondary

characteristics
Progesterone → Controls the development of the
endometrium

J Testis Testosterone → Regulates the development of the

male sex organ in the embryo; controls
male secondary characteristics

a. Melatonin
 1. Too much: Melatonin production varies among individuals, but large doses
cause drowsiness, reduced core body temperature, reproductive system
performance issues, and potential antioxidant effects, though their purpose is not
yet established.

2. Too little: Melatonin deficiencies cause sleep disruptions and insomnia, affecting
neurodegenerative disorders like Alzheimer's and senile dementia.
Supplementation can treat these issues after medical diagnosis.

b. Oxytocin
1. Too much: Excessive oxytocin intake can lead to BPH in males, uterine
contractions during labor, and oversensitivity to others' emotions in healthy young
adults, causing issues with urination and uterine function.

2. Too little: Oxytocin deficiency, a hormone deficiency, can affect uterine

contractions, milk flow, and emotional bonds, leading to symptoms like irritability,
anxiety, orgasm difficulty, and disturbed sleep.

c. Antidiuretic hormone (ADH)

1. Too much: Excessive production of vasopressin can lead to increased kidney
water retention, resulting in SIADH, a condition where the body's sodium levels
are diluted.

2. Too little: Lack of vasopressin leads to kidney excretion of excess water, causing
frequent urination, dehydration, and low blood pressure. Diabetes insipidus is
caused by kidney inability to respond to ADH. Desmopressin is used.

d. Adrenocorticotropic Hormone (ACTH)

1. Too much: High cortisol levels, caused by Cushing's disease or adrenal gland
damage, can lead to weight gain, high blood pressure, muscle weakness, and
fatigue, affecting the pituitary gland.

2. Too little: Adrenal insufficiency can cause weight loss, appetite loss, weakness,
vomiting, nausea, and low blood pressure. Low adrenocorticotropic hormone
(ACTH) levels can be caused by pituitary gland conditions like Cushing's
syndrome or hypopituitarism, caused by adrenal tumors or long-term
corticosteroid use.

e. Human Growth Hormone (HGH)

 1. Too much: Joint pain, headaches, enlarged hands and feet, cardiomegaly,
Gigantism, GH deficiency, pituitary adenoma, Noonan syndrome, and
Acromegaly are common symptoms of GH imbalance.

2. Too little: Poor growth, reduced well-being, increased fat, increased risk of heart
disease, weak heart muscles, and bones, and dwarfism are all associated with
this condition. Proctatin

f. Proctatin
1. Too much: disrupts the reproductive system, reduces hormone production, and
prevents egg release during menstruation. Causes include stress, nipple
stimulation, and medication intake, while in females, it's caused by pregnancy
and stress.

2. Too little: Low prolactin levels, rare but potentially indicative of a pituitary
disorder, can affect breastfeeding, immune responses, and bone strength,
potentially leading to osteoporosis if left untreated.

g. Thyroxine
1. Too much: Hyperthyroidism or overactive thyroid, while extremely low levels
may lead to Hypothyroidism and Myxedema.

2. Too little: Low thyroid hormone levels can alter fat processing, leading to high
cholesterol, atherosclerosis, and potentially serious heart-related issues like
angina and heart attack.

h. Calcitonin
1. Too much: Calcitonin excess may indicate medullary thyroid carcinoma (MTC), a
rare disease caused by abnormal growth of thyroid C cells in the medulla,
potentially leading to MTC.

2. Too little: Elevated calcitonin levels may indicate C-cell hyperplasia or MTC,
while undetectable levels do not cause any negative symptoms related to blood
calcium levels.

i. Parathyroid Hormone (PTH)

1. Too much: Causes calcium levels in your blood to rise too high, which can lead
to health problems such as bone thinning and kidney stones.

2. Too little: Hypoparathyroidism is a condition where the parathyroid glands

produce too little PTH, leading to a decrease in calcium and an increase in
phosphorus levels.
j. Thymosin
 1. Too much: An overproduction of thymosin would increase the production of T
cells leading to an overproduction of lymphocytes leading to lymphocytosis and
could result in an overactive immune system.

2. Too little: Thymosin hormone deficiency can lead to compromised immune

function, increased susceptibility to infections and autoimmune disorders like
Rheumatoid arthritis, Type 1 diabetes, and Lupus.

k. Adrenaline
1. Too much: High blood pressure, weight loss, anxiety, and an increased risk of
heart attack and stroke are all potential health risks.

2. Too little: Adrenal insufficiency is rare but can cause symptoms like fatigue,
body aches, weight loss, low blood pressure, lightheadedness, hair loss, and skin
discoloration.

l. Insulin
1. Too much: Elevated insulin levels can lead to weight gain, worsening insulin
resistance, hyperinsulinemia, metabolic syndrome, high blood pressure, and
other related conditions.

2. Too little: Insulin deficiency leads to glucose accumulation in the blood, causing
symptoms like weight loss, diabetic ketoacidosis, dehydration, and
hyperglycemia, causing fatigue, hypotension, infections, and comatose.

m. Glucagon
1. Too much: Hyperglucagonemia and Glucagonoma Syndrome are rare
pancreatic tumors causing high blood sugar, skin rashes, weight loss, diabetes,
anemia, and inflammation. Symptoms typically affect 50-70 year olds, with
surgery or chemotherapy possible.

2. Too little: Hypoglycemia, a condition where blood sugar drops below 70 mg/dL,
is common in Type 1 Diabetes and Type 2 Diabetes. Diabetes mellitus, a
metabolic disease characterized by hyperglycemia due to defects in insulin
secretion or action, is a common symptom of this condition.
n. Estrogen
1. Too much: High estrogen levels in women can lead to heavier, irregular periods,
weight gain, fatigue, PCOS, and lower sex drive, while in men, it can cause
enlarged breasts, erectile dysfunction, and infertility.
 2. Too little: Low estrogen can delay puberty, prevent sexual development, and
reduce vaginal lubrication, while low estrogen can lead to abdominal fat, weak
bones, and increased risk of cardiovascular disease.

o. Progesterone
1. Too much: High progesterone levels can cause symptoms such as breast
swelling, bleeding, anxiety, agitation, and depression.

2. Too little: Low progesterone levels can lead to symptoms such as infertility,
mood swings, spotting, and irregular cycles.

p. Testosterone
1. Too much: Can lead to body hair growth, mood disturbances, acne, enlarged
prostate, male and female masculine features, infertility, obesity, and metabolic
disorders.

2. Too little: Can cause feelings of sadness, memory and concentration issues, low
motivation, self-confidence issues, erectile dysfunction, increased body fat, and
cholesterol metabolism effects.

2. Chromosomes and DNA Structures

What is a Chromosome?
- is a packaged and organized chromatin, a complex of macromolecules found in cells,
consisting of DNA and protein.
→ DNA – deoxyribonucleic acid
→ RNA – ribonucleic acid
Function
- It carries the HEREDITARY information in the form of GENES.

Where are the CHROMOSOMES & DNA located?

📍 Additional Information!

- The GENES are segments of the DNA. These GENES carry the genetic information of
an organism.

Human Chromosomes
- 23 pairs or 46
- 22 body chromosomes/ autosomes
- 1 sex chromosome

📍Definition of Haploid and Diploid

📍Parts of a Chromosome

📍Types of Chromosomes
Structures of DNA
> Pioneers of DNA Model
- James Watson & Francis Crick, 1953

📍Nucleotide/ Basic Structural Unit of DNA

📍The Central Dogma of Molecular Genetics
- States that pattern of information that occurs in our cells are:
1. From existing DNA to make new DNA (replication)
2. From DNA to make new mRNA (transcription)
3. From mRNA to make new proteins (translation)

- The central dogma of molecular biology explains the flow of genetic information, from
DNA to RNA (transcription) to make a functional product, a protein (translation)

📍 The Comparison Between DNA and RNA

📍Protein Synthesis
📍 DNA Mutation
- is a permanent alteration of nucleotide sequence.

What are the Factors that Cause DNA Mutation?

1. Radiation
2. Chemical
3. Infectious Agents
Types of Mutation

1. Gene Mutation - a change in one or more genes can lead to genetic disorders or
illnesses.
 2. Chromosomal Mutation - changes to the structure or number of chromosomes.

Five types of Chromosomal Mutation

Normal DNA Sequence

1. Deletion
a. Loss of a part
 b. Loss of large regions of a chromosome
c. Cri-du-chat or cat cry syndrome

2. Duplication
a. Extra copies
b. Duplication of a few basses
c. Case of Camille Trinidad extra finger

3. Inversion
a. Reversed
 b. The order of genes in a the chromosome is inverted
c. Opitz-Kaveggia Syndrome

4. Insertion
a. Addition
b. The addition of one or more nucleotide base pairs into a DNA sequence.
c. Huntington’s Disease

5. Translocation
a. Rearrangement
b. Part of one chromosome is transferred to another chromosome
c. Down Syndrome