Interactive classes - MK and CC Flashcards
What type of epithelium is the epidermis?
Keratinizing stratified squamous epithelium.
Are eccrine sweat glands exocrine or endocrine glands?
Exocrine glands because they have a duct.
What functions does the skin perform and which structures contribute? - UV protection
Melanocytes
What functions does the skin perform and which structures contribute? - Temperature regulation
Vascular plexus, sweat glands, hair
What functions does the skin perform and which structures contribute? - Immune surveillance
Langerhans cells, keratinocytes
What functions does the skin perform and which structures contribute? - Waterproofing
Stratum corneum, sebum
What functions does the skin perform and which structures contribute? - Psychosexual/social function
Hair, pigmentation, apocrine glands
What functions does the skin perform and which structures contribute? - Mechanical barrier
Epidermis, dermis, subcutis
What functions does the skin perform and which structures contribute? - Insulation
Subcutaneous fat
What functions does the skin perform and which structures contribute? - Calorie storage
Subcutaneous fat
What functions does the skin perform and which structures contribute? - Sensory system
Merkel cells, free nerve endings, sensory organs and fibres
What vascular and cellular processes have resulted in the accumulation of neutrophils at the site of inflammation?
Vasodilatation
Increased vascular permeability and oedema
Emigration of neutrophils and macrophages
How does granulation tissue form?
Angiogenesis (vascular proliferation)
Fibroblast proliferation, controlled by macrophages
Which cells are responsible for production of collagen in the healing wound?
Fibroblasts produce collagen, controlled by macrophages
How does the scar differ from the adjacent dermis?
More cellular (fibroblasts)
Thin collagen
No pilosebaceous units or eccrine sweat glands
How does the overlying epidermis differ from the adjacent epidermis?
Hyperplastic epidermis = pseudoepitheliomatous hyperplasia
This will resolve over time
Describe the shapes of the 3 types of epithelial cells
- Squamous = thin and flat
- Columnar = almost oblong shaped
- Cuboidal = all sides equal
What is the Most common type of epithelium?
Stratified Squamous Epithelium
Describe the Stratified Squamous Epithelium
Stratified = cells pile on top of each other
Stratification is necessary at sites of friction with the risk of mechanical damage
Squamous = cells are flat
Squamous epithelium in internal organs appears white on naked eye examination
Stratified Squamous Epithelium could be…
keratinised or non-keratinised
What is keratin?
Keratin is the protein present in skin cells produced by keratinocytes
Keratin makes the skin impervious
What is the most superficial part of the skin?
consists of dead keratinised cells which makes the skin waterproof
The oesophagus is joined to the stomach at the…
oesophago-gastric junction (OGJ)
What does oesophagus and stomach mucosa look like?
White and Pink
List Some of the organs
lined by squamous epithelium
Skin
Mouth and tongue
Oesophagus
Anal canal
Vagina
Cervix
What does Columnar epithelium appears as on naked eye examination?
pink/red
Where can I find columnar epithelium?
- Respiratory tract = trachea & bronchi
- Gastrointestinal tract = stomach, small & large intestines
What is the function of mucus secreted by columnar epithelium?
Protects the lining - in the stomach
Traps dust particle - respiratory tract
Acts as lubricant - large bowel and female genital tract
Columnar epithelium of the large intestine consists of test tube like structures termed…
crypts
The Upper Respiratory Tract: part of the larynx, trachea & bronchi are lined by …
pseudo-stratified columnar epithelium
Why is it called Pseudostratified Ciliated Columnar Epithelium?
because all nuclei do not reach the surface
Where are Cuboidal Cells found?
Found in glands which secrete specialised fluids, i.e.
- Salivary glands
- Sweat glands
- Endocrine glands secrete hormones
- Breast produces milk
What does fibrous tissue look like on the breast?
White firm appearance
What does fibrous tissue look like underneath a microscope?
Pink
Describe the composition of a single breast gland
A single breast gland is lined by cuboidal cells (more round than a cube); the lumen contains milk.
What are the Three types of muscle found in the body?
Skeletal muscle – Most common muscle: limbs, chest wall, abdominal wall
Smooth muscle – Most internal organs: stomach, small & large intestines, blood vessels, uterus
Cardiac muscle – Only in the heart
Why are Striations important in skeletal muscles?
for the contractile function of the muscle cells
What is the name of the thick muscle in the uterus? why is it so thick?
myometrium = smooth muscle fibres with cigar-shaped nuclei; no striations
endure the pressure during pregnancy
What is lipofuschin?
= Brown pigment is end product of break down of the muscle (wear and tear)
What is mesentery?
Fat as connective tissue of the small bowel
What is adipose tissue/cells
Fat cells
Why does adipose tissue/cells look honeycomb shaped under a microscope but when to the naked eye it is yellow?
processing in different chemicals the fat leaches out
Why is fibrous tissue important?
Important connective tissue due to its strength e.g. tendons
Important in healing of wounds to form scars
What does fibrous tissue consists of?
Consists of long fibres containing collagen
Fibroblasts produce the protein collagen
In healed wounds, scar tissue and fibrous tissue are used interchangeably
What produces elongated fibres in fibrous tissue?
fibroblasts
Give an example of scarring?
When the myocardium dies the muscle is replaced by scar tissue
What surrounds arteries and veins?
fat as the connective tissue
What type of muscle is in all nerves not in the heart?
smooth muscle
What do nerve cells look like under the microscope?
wavy/serpentine
The oesophagus is lined by:
Non-keratinised stratified squamous epithelium
Which organ contains intercalated discs?
The heart
Define normal skin and where can you find it?
Baseline - epidermis + dermis
Limbs and chest
What does Individual keratinised squamous epithelial cells appear as under the microscope?
pink
Squamous epithelium is held together by intercellular structures termed …
desmosomes
Skin from the head/scalp has numerous…
hairfollicles that can go deep in subcutaneous fat
What is responsible for dandruff?
sebaceous glands
What does skin the face contain?
hair follicles and sebaceous glands
Describe how acne can be caused
Sebaceous glands are controlled by sex hormones
Secretions are rich in lipid
Describe skin from the back
thin epidermis but thick dermis; no hairs
Describe the skin from the palms of hand or soles of the foot
thick cornified layer of the epidermis (thick skin)
What are the 5 layers of the epidermis?
Extensively
Stratum cornium; cornified layer
Stratum lucidium; only found in thick skin; it’s the pink thin layer of uniform tissue which separates the SC from SG
SG: Stratum granulosum; granular layer
SS: Stratum spinosum; spinous or prickle cell layer; desmosomes are present in this layer
SB: Stratum basalis; basal layer or germinative layer
When irritated from scratching as in eczema what happens to the epidermis?
The epidermis develops a thick cornified layer
The stratum spinosum also becomes thick, a condition termed acanthosis
Name the organs lined by non-keratinised squamous epithelium: Top to Bottom
M for Mouth
E for Esophagus
A for Anal canal
C for Cervix
V for Vagina
What does the dermis layer primarily consist of?
collagen and elastin fibres which are produced by the fibroblasts
What does Excessive sun exposure do to the dermis?
damages the dermis to produce solar elastosis & appears featureless
Loss of elasticity produces wrinkles as in aging. The protruding lesion is appropriately named as a…
cutaneous horn and consist of keratin
Where are eccrine glands found?
present all over the body
Where are apocrine glands found?
in the axilla, nipple and groin
What are eccrine glands responsible for?
responsible for control of body temperature
What are apocrine glands responsible for?
responsible for body odour
Which type of sweat gland is larger?
Apocrine
What are the 2 layers of cells eccrine glands consist of?
Inner secretory epithelial cells and the outer myo-epithelial cells
What is the shape of the cells lining the glands?
Cuboidal epithelium
What is the medical condition which uses the sweat test for diagnosis?
Cystic fibrosis
What are the main constituents of sweat?
Water and
Salts/Sodium chloride
Where is the sweat contained in apocrine sweat glands?
In the lumen
Why does sweat smell?
bacterial fermentation
Where do melanocytes originate?
neural crest - the part of the embryo which will develop into brain and nerves
When do melanocytes migrate to the skin?
During embryological development
How can congenital naevus or birth marks be made?
Abnormal migration and concentration of melanocytes in a single site
What controls melanin production?
enzyme tyrosinase
Where are melanocytes found?
found between the epithelial cells (keratinocytes) and have clear spaces around them (arrows)
What is the concequence of congenital naevus (birthmarks)
Leads to staring and teasing
High risk of developing melanoma (a type of skin cancer) at a young age
What does Lack of enzyme tyrosinase lead to?
albinism
What is Vitiligo thought to be?
an autoimmune disease where one’s immune system attacks the melanocytes
What are the Major Types of Skin Cancer?
Malignant melanoma (MM) - from melanocytes
Squamous cell carcinoma (SCC) - resembles normal skin in production of keratin
Basal cell carcinoma (BCC) - resembles cells of basal layer of the epidermis
Which skin cancers are Non melanoma skin cancer (NMSC)?
Squamous cell carcinoma (SCC)
Basal cell carcinoma (BCC)
Prognosis of all cancers is assessed using the TNM stage thus:
T = tumour size (diameter) or depth of invasion
N = node (whether there is lymph node metastasis or not)
M = metastasis to the liver, lung, bone etc.
Malignant Melanoma (MM) has the Third most common cancer of the skin.
Why does it also have the worst prognosis of all skin cancers?
Has propensity to spread to the lymph nodes, lungs, liver and brain
What is acral malignant melanoma?
Patients of African, Japanese and Asian origin tend to develop melanoma in non-sun exposed areas like the feet and hands
Microscopically the melanin from the cancer cells is present as …
dispersed or collections of brown /black pigment
Squamous cell carcinoma (SCC) is the Second most common cancer of the skin. What can it be classified as (3 classifications)?
well differentiated - when the cancer cells produce lots of keratin
Moderately differentiated - moderate amount of keratin
Poorly differentiated - little or no keratin
i.e. graded on how closely the cancer resemble skin
Can SCC also spread to lymph nodes and other organs?
Yes
What is the Histology of Well differentiated SCC of the skin with good prognosis
Lots of keratin production
Round base
Minimal invasion of dermis
What is the histology of Moderately differentiated SCC of the skin; moderate prognosis?
Moderate amount of keratin
Irregular base
More invasive
What must we use to identify poorly differentiated SCC and what would we observe (histology)?
infiltrating the stroma in a haphazard (random) manner; no keratin production
What is the most common cancer of the skin in the western world?
Basal Cell Carcinoma (BCC)
Describe the ket features of Basal Cell Carcinoma (BCC) (4)
Infiltrates locally, but rarely spreads to other organs
Tends to be multiple
Tends to recur
Can be disfiguring if on the face
What do basal cells look like under the microscope?
BCC cells are blue
Excision
the act or procedure of removing by or as if by cutting out
In Advanced squamous cell carcinoma,
What major blood vessels are located beneath the cancer? (hint near neck and ear)
Carotid arteries and jugular veins
List 4 functions of the keratinised layer of the skin
- Protects against infection
- Prevents dehydration
- Consist of dead cells
- Increases in thickness when irritated
List 4 things that can occur due to Excessive sun exposure
- Increases melanin pigmentation/tanning
- Causes solar elastosis
- Causes wrinkling
- May lead to skin cancer
Thick skin is: T/F
- Held together by desmosomes (T)
- Present on the back (F); has thick dermis, not epidermis
- Present on the sole of the foot (T)
- Present on the head (F)
True:
Held together by desmosomes (T)
Present on the sole of the foot (T)
What are the 3 categories of inflammation?
Acute inflammation e.g. acute tonsillitis when the neutrophil is the dominant cell
Chronic inflammation e.g. chronic gastritis when the lymphocyte is the predominant cell
Active chronic inflammation when there is a mixture of neutrophils and lymphocytes e.g. active chronic gastritis
What causes Breast abscess or mastitis?
stagnation of milk which gets infected
What is the first cell to appear at the sight of inflammation and why?
Neutrophils
to ‘eat’ the bacteria or the antigen causing the inflammation
What are the 5 theoretical cardinal signs of inflammation?
- Hot (calor)
- Red (rubor)
- Swollen/oedema (tumor)
- Pain (dolor)
- Loss of function (functio laesa)
When does an abscess occur?
when inflammation causes tissue destruction to form a cavity containing lots of neutrophils and dead tissue (the pink material)
What are the cells of chronic inflammation?
Lymphocytes - one nucleus and a small amount of cytoplasm
Specifically -
B lymphocytes differentiate to plasma cells to produce antibodies
T cells help in the process of inflammation
What do antibodies make the bacteria more?
more palatable (opsonise) for the polymorphs
Can you name antibodies produced by plasma cells?
IgM
IgG
IgA
IgE
IgD
What do eosinophils associate with?
with allergic reactions such as asthma and parasitic infections
What mediates the accumulation of Eosinophils?
IgE produced by plasma cells
Describe what Eosinophils look like
the cytoplasm contains granules which take up the pink stain avidly
What is a polyp?
A polyp is an abnormal growth protruding
growth into a cavity
Why is the polyp pale on microscopy?
excess fluid called oedema
What do Monocytes look like in a blood smear?
Has a single reniform (kidney – shaped) nucleus and lots of cytoplasm
What is the function of a monocyte?
Functions as a phagocyte, but does not do this in the circulation but in the tissues where it is known as macrophage or histiocyte
A macrophage is a cell of…
chronic inflammation
When macrophages accumulate to form a collection of cells – this is known as a
granuloma
What is a Horse-Shoe Shaped Giant Cell?
When macrophages join up together to create a single cell with multiple nuclei
Which condition is associated with this horseshoe-shaped Langhan’s giant cell?
TB
What are the causes of poor wound healing? (6)
Poor circulation due to atheroma
Presence of infection
Excess movement e.g. fractures
Foreign body in the wound e.g. suture material
Vitamin C deficiency
Diabetes mellitus is also associated with poor circulation
What does Granulation Tissue consist of?
Oedematous fibrous tissue
New blood vessels
When does granulation tissue occur/appear?
Acute and chronic inflammation
Granulation Tissue is essential for the…
Is essential for the healing process
skin grafting
What is Wound Healing by Primary Intention?
when the skin edges come together properly
What happens to The material used to suture in wound healing by primary intention?
the wound is usually destroyed by macrophages which join up to create foreign body giant cells
What is healing by secondary intention?
occurs when the wound is too large for the edges to come together or there are other factors that interfere with wound healing.
Describe Wound Healing by Skin Graft
Sometimes the wound is too large even for healing by secondary intention
A skin graft from another site is applied
What does excess accumulation of scar tissue lead to…
keloid formation
What are the 4 adaptations of cells they can do in a hostile environment?
Metaplasia
Hypertrophy
Atrophy
Hyperplasia
What is metaplasia?
Occurs when one type of mature cell differentiates to another form of mature cell
Metaplastic epithelium is associated with high risk of…
developing cancer
Examples of Metaplasia in the Oesophagus?
Squamous epithelium changes to columnar epithelium = Barrett’s oesophagus due to gastric contents reflux
Examples of Metaplasia in the Bronchus
Pseudostratified ciliated columnar epithelium changes to squamous epithelium due to smoking
Examples of Metaplasia in the Cervix
Columnar endocervical mucosa infected by HPV changes into squamous epithelium
What is Barrett’s Oesophagus?
Acid reflux from the stomach into the oesophagus
This causes inflammation -> reflux oesophagitis
The squamous epithelium (white) is replaced by columnar epithelium (pink) to cope with the acidity -> gastric metaplasia or intestinal metaplasia
Barrett’s oesophagus is associated with risk of adenocarcinoma
Describe Squamous Metaplasia in Bronchus
Smoking destroys the ciliated pseudo-stratified columnar epithelium which differentiates into a more resilient squamous epithelium
Squamous metaplasia has an increased risk of squamous cell carcinoma of the lung
What is Hypertrophy?
Can be physiological or pathological
Hypertrophy occurs due to increase in the size of cell resulting increase in the size of the organ
What is Atrophy? Use an example
Atrophy occurs when the cell decreases in size resulting in shrinkage of the organ
e.g. post menopausal atrophy of the uterus due to lack of oestrogen stimulation
When does hyperplasia occur?
when there is increase in number of cells which results in increase in the size of the organ
Give an example of hyperplasia
the increase in number of cells in the prostate in older men resulting in condition termed benign prostatic hyperplasia (BPH)
This causes problems with urination
Can result in urine retention
A 32-year-old woman presented with a
breast abscess. Which are the predominant
cells in an abscess?
Neutrophils
Metaplasia is associated with an increased
risk of cancer. What causes metaplasia?
Cells differentiate from one form of mature cells to another in the organ
