Anatomy and Physiology | Assignment

Anatomy and Physiology
1

1.1.
Shape of thyroid gland is like a butterfly and central isthmus connects two wings. Thyroid
tissue contains follicles comprising of stored protein which is called as colloid.
These glands are triangular-shaped. Outer part of adrenal cortex is termed as adrenal cortex
and inner as adrenal medulla.
These are the two pairs of the small glands surrounded in the surface of the thyroid gland.
One pair of parathyroid gland present on each side.
Testes are present in males and these are two ovular glands located in the scrotum. Ovaries
are pinkish grey in colour and these are oval shaped (http://www.healthcommunities.com;
https://www.wisegeek.com).
Pancreas are located in the abdominal region, below and behind the stomach. Both exocrine
and endocrine pancreas are present in the human body (Kemp).
Pineal gland size is small and it is of pine shape (Bailey, 2019; Marieb and Hoehn, 2019;
Thakare, 2015; https://training.seer.cancer.gov/).
1.2.
Hormonal production in the body is usually controlled by the negative feedback. Through this
mechanism, concertation of the hormone in the body can be maintained within the normal
range. It can be illustrated through the example of release of thyroid hormone. Anterior
pituitary gland is responsible for sending signals to the thyroid for the release of thyroid
hormones. Augmented levels of these hormones in the blood circulation send feedback to the
hypothalamus and anterior pituitary gland for inhibition of further signalling to the thyroid
gland. Thryocytes of the thyroid gland can be exemplified as the hormone producing cell.
Hormones are produced by the glands and sent to the bloodstream for further distribution to
the different tissues (Marieb and Hoehn, 2019; Thakare, 2015; Kemp;
https://www.pituitary.org.uk).
1.3.
Release stimuli for hormones can be categorised into humoral stimuli, hormonal stimuli and
neural stimuli.
2

Humoral stimuli: Humoral stimuli for hormones depend on alteration in the extracellular
fluids in the form of change in the ion concentration in the blood. Increased blood glucose
levels lead to the release of insulin through the pancreas. Further, drop in the insulin levels
would trigger the pancreas to stop the release of insulin.
Hormonal stimuli: Hormonal stimuli depends on the release of one hormone due to stimuli of
another hormone. Hormones produced by the hypothalamus are responsible for the
stimulation of anterior portion of the pituitary glands. Consequently, anterior pituitary
releases thyroid stimulating hormone which is responsible for the stimulation of thyroid gland
for the production of hormones such as T3 and T4 (https://courses.lumenlearning.com).
Neural stimuli: Nervous system directly stimulate the endocrine glands for the release of its
respective hormones. Neuronal signalling originated from the sympathetic nervous system
directly act on and stimulate the adrenal medulla for the release of hormones epinephrine and
norepinephrine in response to stress (Marieb and Hoehn, 2019; Thakare, 2015).
2.1.
Human ear consists of three portions such as external ear, middle ear and internal ear.
External ear consists of three parts such as pinna, external auditory meatus and tympanic
membrane.
External auditory meatus: It is a tubular portion supported through cartilage on the external
end and bone on the internal end.
The tympanic membrane: It separates the tympanic cavity from the external auditory meatus.
It is oval in shape and it is thin and semi-transparent. Central part of this membrane is called
as umbo.
Functions of external ear: Sound waves get directed towards tympanic membrane. These
sound waves exert pressure changes over the tympanic membrane surface. The cerumen is
useful in preventing entry of foreign bodies into the ear.
Middle ear comprises of following parts: Middle ear also comprises of small flexible chain
consisting of three smaller bones called as ear ossicles - the malleus (hammer shaped), the
incus (anvil shaped) and the stapes (stirrup shaped). Middle ear also comprises of two
skeletal muscles such tensor tympani and stapedius.
3

Functions of middle ear: Tympanic membrane behaves as resonator which produces
vibrations of sound. It transmits sound waves from external to internal ear and also increases
the intensity of soundwaves.
In internal ear there is a body cavity which is covered with hard periotic bone which contain
perilymph. Membranous labyrinth floats in the perilymph. This membranous labyrinth
comprises of semi-circular ducts, utricle, saccule, endolymphaticus and cochlea.
Internal ear performs function of hearing and balancing (https://www.mydr.com.au).
Huma eye: Human eye comprises of several parts such as cornea, lens and retina. In addition
to this, it also contains iris, pupil, aqueous humour and vitreous humour. Cornea is curved
and it is present in front side of iris and pupil. Lens is present behind the iris. Retina is the
lining of the back of the eye. Retina comprises of cells sensing photoreceptors. Retina also
comprises of nerve cells termed as rods and cones which convert light into the nerve impulses
which transmit to the brain through optic nerve. Cones are attributable to the sharp, colour
vision and central vision. Rods are attributable for the night and peripheral vision. Optic
nerve is located at the end of eyes behind the retina. It is responsible for carrying nerve
impulses from photoreceptors to the brain. Eyeball is divided into two sections such as
anterior and posterior chamber. Anterior chamber extends from the inside portion of cornea
to the front surface of lens. Posterior chamber back surface portion of the lens to the retina.
Iris consists of collagen framework and muscle fibre which are located behind the cornea and
also in front of the lens. Conjunctiva is present in front of the eye. Sclera is the opaque,
fibrous and protective outermost layer of the eye which provides protection to the eye (Shiel,
2018; Garrity; https://byjus.com).
Nose is divided into different parts such as nasal cavity, olfactory epithelium, cribriform
plate, olfactory nerve, olfactory bulb, olfactory tract and olfactory cortex.
Nasal septum divides nasal septum into right and left passages which are lined with mucosa.
Olfactory epithelium contains olfactory nerve cells and nerve receptor cells which send
impulses to the olfactory bulb.
Cribriform plate is the extension of the ethmoid bone and it separates the nasal cavity from
the brain. It transmits olfactory nerve fibres which carry sense of smell
(https://www.wisegeek.com; https://www.wisegeek.com).
4

Olfactory nerve is the first cranial nerve which transmits sensory data to the brain. Also, it is
responsible for the sense of smell. Nerves of the olfactory receptors are situated within the
mucosa of the nasal cavity (Healthline's Medical Network, 2015).
Olfactory bulbs: It is a bulb shapes structure located in the forebrain, the point at which
olfactory nerves end and the olfactory tract begins (Purves, Augustine, & Fitzpatrick, 2001).
Olfactory tract is the band of nerve fibres which extends from the olfactory bulb to the
olfactory cortex of brain. Olfactory tract connects olfactory tract to the different centres
within the brain.
Olfactory cortex: Olfactory cortex is the area of cerebral cortex which processes information
related to the odours. Also, it receives signals from the olfactory bulb (Bailey, 2019).
Tongue: Tongue contain gustatoreceptors which are responsible for the taste. Tongue is a
muscular organ located in the mouth and it is covered with mucosa. Papillae, which are
present in the form of tiny bumps provide tongue with rough texture. Tongue contain nerves
which detect and transmit taste signals to the brain. Different structures are located at the
different portions of the tongue for taste identification. Foliate papilla is vertical in shape and
located on the posterior lateral edge of the tongue. Fungiform pailla is club shaped and
located at apex and on the sides on the tongue. Circumvallate papilla are dome shaped and
located at back side of the tongue. Filiform papilla is cone shaped which covers most of the
portion of the tongue (Hoffman, 2014; Wanjek, 2006; Marieb and Hoehn, 2019; Thakare,
2015).
2.2.
Skin is primarily consisting of two layers such as epidermis and dermis. Epidermis comprises
of cells such as keratinocytes, melanocytes, Langerhans cells and Merkel cells. Epidermis is
divided into several sublayers such as stratum corneum, stratum lucidum, stratum
granulosum, stratum spinosum and stratum germinativum. Dermis is present beneath the
epidermis and it consists of connective tissues and nerve endings. Dermis consists of hair
follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood
vessels. Dermis is structurally differentiated into two regions such as papillary region which
is superficial region present adjacent to the epidermis and reticular region which is deep
thicker area (Minochi, and Choi, 2019; Marieb and Hoehn, 2019; Thakare, 2015).
5

2.3.
Urinary system and homeostasis: Renal system comprises of 2 kidneys, 2 ureter, urinary
bladder and urethra. Urinary system plays important role in the homeostasis of the body
through regulating fluid and electrolyte balance. It also regulates acid balance to create stable
environment for cell and tissue metabolism. Urinary system maintains homeostasis through
balancing solute and water transportation. Moreover, it excretes metabolic waste and retain
nutrients. Kidneys remove waste products of the body through filtering the blood received
from the renal arteries. Kidneys also plays role in the maintaining pH of the blood 7.4
through removing hydrogen ion. Equal proportion of fluid intake and fluid loss are essential
for the maintaining homeostasis. Kidney removes excess fluid from the body and maintain
optimum fluid and salt balance. Kidneys respond to the fluid imbalance though increasing or
reducing water content in the urine.
Uterus is the long, thin tube which is made of smooth muscles.
Bladder wall comprise of rugae and a layer of detrusor muscle.
Female urethra is narrow (4 cm long) and male urethra is long (17-20 cm) (Marieb and
Hoehn, 2019; Thakare, 2015; Hartsock).
3.1.
DNA is made up of small molecules termed as nucleotides. Each nucleotide comprises of
different groups such as phosphate group, a sugar group and nitrogen base. Four different
types of nitrogen bases such as adenine (A), thymine (T), guanine (G) and cytosine (C) are
present in the DNA. Order of these nitrogen bases are attributable for determining the DNA’s
instructions or genetic code. Human DNA comprise of approximately 3 million bases. DNA
sequence in the genes are based on the order of nitrogen bases. Double helix forms though
attachment of nucleotides to form two long strands and spiral of these two strands. Phosphate
and sugar molecules are present at the sides and nitrogen bases are present at the centre.
Nitrogen bases of one stand pairs with the nitrogen bases of another strand. Pairing formed
between adenine and thymine and guanine and cytosine (Lewis, 2010; Rettner, 2017).
3.2.
Process of DNA replication
6

The process of DNA duplication is termed as DNA replication.
DNA replication process comprise of four steps such as replication fork formation, primer
binding, elongation and termination.
Replication fork formation: In this step, enzyme DNA helicase unwind DNA to break the
interaction between the base pairs. DNA helicase break the hydrogen bonding between the
bases pairs which results in the separation of strands into Y shape which is known as
replication fork. It is the template for the initiation of replication.
Primer binding: After the separation of DNA strands, a short piece of RNA called a primer
binds to the 3' end of the strand.
Elongation: In elongation process, DNA polymerase create a new strand. DNA polymerase
III binds to the strand at the point of primer and consequently ass new base pair
complementary to the parent strand. The lagging strand replicate through binding to the
multiple primers. This process results in the formation of discontinuous strands.
Termination: After the formation of both continuous and discontinuous strands, enzyme
termed as exonuclease removes all the RNA primers from the original strand. Removed RNA
primers later replicate with appropriate bases. Another exonuclease involves in the proof
reading of the newly formed DNA for checking, removing and replacing any type of errors.
Single unified strand formed trough joining the DNA ligase enzyme with the Okazaki
fragments. DNA polymerase enzyme termed as telomerase plays role in the synthesis of
telomere sequences at the end of DNA sequences. After completion of this step, parent and
its complementary DNA strand coils into double helix shape. Finally, replication results in
the formation of two DNA molecules consisting one strand from the parent molecule and
another from the new strand (Lewis, 2010; Pandirajan, 2018).
3.3
Eye color is the good example of inherited characteristics. Genes control the inherited traits
and complete set of genes within the organism genome which is termed as genotype.
Genotype influences the phenotype of an individual. Genotype for eye colour of an individual
comprise of one brown eye allele (B) and one blue eye allele (b). It results in the individual’s
phenotype with brown eye because brown eye is the dominant and blue eye allele is recessive
(Lewis, 2010; https://www.yourgenome.org).
7

Inheritance of eye colour:
 B- dominant brown eye allele
 b- recessive blue eye allele
o BB- brown eyes
o Bb- brown eyes
o bb- blue eyes
4.1.
Female reproductive organs:
Vulva comprise of urethral opening and plays role in urine passing. Vulva and external parts
of the female reproductive organs comprise of parts and tissues such as mons pubis, pudendal
cleft, labia majora, labia minora, Bartholin's glands, clitoris, and vaginal opening.
Labia majora comprises of a pair of rounded folds of the skin and adipose tissue. These are
helpful in covering and protecting inner sensitive structures of vulva.
Labia minora comprises of pair of thin cutaneous folds which is component of inside part of
labia majora. During stimulation due to blood vessel engorgement labia minora swells and
become sensitive.
Clitoris is sensitive and covered by the fold of skin called as prepuce. Upon stimulation,
clitoris filled with blood and become erect.
Bartholins glands: Bartholins glands are the two pea sized glands situated posterior to the
right and left vaginal opening. These glands help lubricate vagina for intercourse through
secreting mucus.
Mons Pubis: Mons pubis is the rounded mass of fatty tissue covered over the pubic
symphysis of the pubic bones. It contains sebaceous glands which releases substance for
sexual attraction.
Vagina: Vagina is the muscular tube-like organ. It is lined with mucous membrane and it
remain moist due to cells on its surface and through secretions from glands from cervix.
Vagina is an organ for sexual intercourse through which sperm travel to the egg. It is also a
passage for menstrual bleeding.
8

Uterus: Uterus is the thick walled, muscular, pear-shaped organ located behind the urinary
bladder. It plays role in housing and nourishing fertilised egg till foetus is ready to be
delivered.
Cervix: Cervix is the lower part of the uterus which is lines with smooth mucous membrane.
Cervix is the entry point for sperm and channel for the exit of the menstrual blood.
Ovaries: Ovaries are small and paired organs which are located near the lateral walls of the
pelvic cavity. Ovaries play important role in the production of eggs and reproductive
hormones such as oestrogen and progesterone.
Fallopian tubes: Fallopian tubes are narrow and attached to the upper part of the uterus.
Fallopian tubes are lined with the cilia and muscles. Fallopian tubes act as passage for the
eggs to uterus and implantation in the uterine wall (Marieb and Hoehn, 2019; Thakare, 2015;
Knudtson, J., and McLaughlin).
4.2.
Male reproductive organs:
Penis: Penis has long shaft and expanded bulbous shaped tip which is called as glance penis
which is supported and protected by the foreskin. After sexual arousal for men, penis become
erect and prepared for sexual activity. Penis is innervated with the pudental artery.
Scrotum: Scrotum is located behind the penis and it is a pouch like structure. It holds, cover
and protect the testicles. It is also innervated with various nerves and blood vessels. Inguinal
canal connects the scrotum with the abdomen or pelvic cavity.
Testes: Testes are paired rounded glands located in the scrotum. It has two major functions
such as sperm and testosterone along with other androgens. Testes ducts comprise of
seminiferous tubules and vas deferens which are involved in the transportation of the sperm.
Penis: Penis is formed by the corpus, cavernosum, and spongiosum tissue. Head of the penis
is termed as glans which contain passage for urine and seminal fluid. Penis is the organ for
sexual intercourse and urination.
Epididymis: It is long whitish mass of tightly coiled tube which is located back side of the
testes. It stores and transports sperms.
9

Vas deferens: Vas deferens is also termed as sperm duct which is a thin tube of
approximately 30 cm length which starts from the epididymis to the pelvic cavity. It
transports spermatozoa form the epididymis to the ejaculatory duct.
Seminal vesicles: It is sac like pouch which attaches to the vas deferens. Vesicle nourishes
sperm through producing fructose.
Prostate gland: It is a walnut sized structure located below urinary bladder for the ejaculation
of fluid for the nourishment of the sperms.
Bulbourethral gland: It is a pea sized structure located on the sides of urethra beneath the
prostate gland. It produces liquid which lubricates urethra for neutralising acidity with
residual urine.
Seminal gland: These are the pair of glands located beneath the urinary bladder. It produces
and store semen (Marieb and Hoehn, 2019; Thakare, 2015;
https://courses.lumenlearning.com).
4.3.
Reproductive traits and inherited traits
Every individual contains two genomes each having one copy from each parent. Inheritance
is defined as the transmission of genetic material from the parents to the offspring.
Reproductive cells such as egg and sperm contain one set of chromosomes each and they are
haploid. Through fertilisation sperm combine with eggs. Fertilised egg contains two sets of
23 chromosomes. Transmission of the genetic material can be assessed through examining
the characteristics such as eye colour and nose shape. In case, there is mutation in the genetic
material, it can be transmitted from the parent to the child which results in the alteration in
nucleotide sequence and disease in the child (Lewis, 2010; Moulton, 2014;
https://www.yourgenome.org).
10

References:
Bailey, R. (2019). What Is the Function of the Pineal Gland?
https://www.thoughtco.com/pineal-gland-anatomy-373225. Retrieved on 18th Dec. 2019.
Bailey, R. (2019). The Olfactory System and Your Sense of Smell.
https://www.thoughtco.com/olfactory-system-4066176. Retrieved on 18th Dec. 2019.
Garrity, J. Structure and Function of the Eyes.
https://www.msdmanuals.com/en-gb/home/eye-disorders/biology-of-the-eyes/structure-and-
function-of-the-eyes. Retrieved on 18th Dec. 2019.
Healthline's Medical Network. (2015). Olfactory nerves. https://www.healthline.com/human-
body-maps/olfactory-nerve#1. Retrieved on 18th Dec. 2019.
Hartsock, A. How the Urinary System Maintains Homeostasis.
https://study.com/academy/lesson/how-the-urinary-system-maintains-homeostasis.html.
Retrieved on 18th Dec. 2019.
Hoffman , M. (2014). Picture of the Tongue. Human Anatomy.
https://www.webmd.com/oral-health/picture-of-the-tongue#1. Retrieved on 18th Dec. 2019.
Jones, O. (2019). The Nasal Cavity. https://teachmeanatomy.info/head/organs/the-nose/nasal-
cavity/. Retrieved on 18th Dec. 2019.
Knudtson, J., and McLaughlin, J. E. Female Internal Genital Organs.
https://www.msdmanuals.com/en-gb/home/women-s-health-issues/biology-of-the-female-
reproductive-system/female-internal-genital-organs. Retrieved on 18th Dec. 2019.
Knudtson, J., and McLaughlin, J. E. Female External Genital Organs.
https://www.msdmanuals.com/en-in/home/women-s-health-issues/biology-of-the-female-
reproductive-system/female-external-genital-organs. Retrieved on 18th Dec. 2019.
Kemp, S. Anatomy of the Endocrine System.
https://www.emedicinehealth.com/anatomy_of_the_endocrine_system/article_em.htm#what_
is_the_endocrine_system. Retrieved on 18th Dec. 2019.
Lewis, R. (2010). Human Genetics: The Basics. Garland Science.
Marieb, E.N., and Hoehn, K. (2019). Anatomy & Physiology. Pearson Education.
Minochi, R., and Choi, J. (2019). Skin structure and function.
https://www.dermcoll.edu.au/atoz/skin-structure-function/. Retrieved on 18th Dec. 2019.
Moulton, G.E. (2014). Inheritance: Meiosis and Sexual Reproduction.
https://www.infoplease.com/math-science/biology/genetics-evolution/inheritance-meiosis-
and-sexual-reproduction.
Pandirajan, K. (2018). The Cell Cycle. https://teachmephysiology.com/basics/cell-growth-
death/cell-cycle/.
Purves D, Augustine GJ, Fitzpatrick D. (2001). Neuroscience. The Olfactory Bulb. Sinauer
Associates. Sunderland (MA). Retrieved on 18th Dec. 2019.
11

Rettner, R. (2017). DNA: Definition, Structure & Discovery.
https://www.livescience.com/37247-dna.html. Retrieved on 18th Dec. 2019.
Shiel W.C. (2018). https://www.medicinenet.com/script/main/art.asp?articlekey=10586.
Medical Definition of Anterior chamber. Retrieved on 18th Dec. 2019.
Thakare V.N. (2015). Human Anatomy and Physiology. Nirali Prakashan.
Wanjek, C. (2006). The Tongue Map: Tasteless Myth Debunked.
https://www.livescience.com/7113-tongue-map-tasteless-myth-debunked.html. Retrieved on
18th Dec. 2019.
Pituitary & Pineal Glands.
https://training.seer.cancer.gov/anatomy/endocrine/glands/pituitary.html. Retrieved on 18th
Dec. 2019.
Anatomy of the Ovaries. http://www.healthcommunities.com/ovarian-cancer/anatomy.shtml.
Retrieved on 18th Dec. 2019.
What are Testes? https://www.wisegeek.com/what-are-testes.htm. Retrieved on 18th Dec.
2019.
Your hormones. https://www.pituitary.org.uk/information/hormones/. Retrieved on 18th Dec.
2019.
Regulation of Hormone Production.
https://courses.lumenlearning.com/boundless-biology/chapter/regulation-of-hormone-
production/ Retrieved on 18th Dec. 2019.
Structure of Human eye. https://byjus.com/biology/structure-of-eye/. Retrieved on 18th Dec.
2019.
Ear anatomy. https://www.mydr.com.au/hearing-health/ear-anatomy. Retrieved on 18th Dec.
2019.
https://www.wisegeek.com/what-is-the-function-of-the-olfactory-epithelium.htm. Retrieved
on 18th Dec. 2019.
What Is the Function of the Olfactory Epithelium? https://www.wisegeek.com/what-is-the-
function-of-the-olfactory-epithelium.htm. Retrieved on 18th Dec. 2019.
What is DNA replication? https://www.yourgenome.org/facts/what-is-dna-replication.
Retrieved on 18th Dec. 2019.
The Male Reproductive System. https://courses.lumenlearning.com/boundless-ap/chapter/the-
male-reproductive-system/. Retrieved on 18th Dec. 2019.
What is inheritance? https://www.yourgenome.org/facts/what-is-inheritance. Retrieved on
18th Dec. 2019.
12

13