Anatomy and Physiology | Assignment

Anatomy and Physiology
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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.
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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.
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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).
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