Abnormalities of Growth Flashcards
Hypertrophy definition
Increase in cell size
What sort of tissues does it occur in + example?
Permanent tissues such as cardiac and muscle cells
What occurs in muscle hypertrophy?
Growth from adding sarcomeres as well as increase in non-contractile elements such as sarcoplasmic fluid
Hyperplasia definition
Increase in a tissue, so cell growth coupled with proliferation
What sort of tissues does it occur in + example?
renewing tissues, such as stem cells, skin epidermis (when abrasion occurs)
and red blood cells
Resting tissue- very limited, endocrine glands
Neoplasia definition
Abnormal growth and division of cells, often a precursor to tumour development. Growth of a neoplasm is uncoordinated with that of the normal surrounding tissue
Difference between a tumour and cancer
A tumour is a solid or fluid filled cystic lesion that may or may not have been formed from neoplastic cells, that appears enlarged in size.
Cancer is by definition a malignant tumour, whereas tumours can be malignant, benign or precancerous.
neoplasia vs hyperplasia
hyperplasia refers to an abnormal increase in the number of cells, which are a normal component of the tissue, arranged in the normal fashion, whilst neoplasia is the increase in number of cells that appear different to the surrounding tissues.
Benign tumour growth
A mass of cells that lacks the ability to invade surrounding tissue so instead grow by expansion.
Malignant tumour growth
Characterised by anaplasia, invasiveness and metastasis. They invade surrounding tissues and progressively get worse.
Agenesis definition
failure of an organ to develop
Example of agenesis
Potter’s syndrome- describes the typical physical appearance caused by pressure in utero due to oligohydramnios (condition during pregnancy where there is a lack of amniotic fluid) due to bilateral real agenesis. Eventually leads to lung failure which causes death
What is bilateral renal agenesis?
both metal kidneys fail to develop during gestation.
Hypoplasia definition
underdevelopment or incomplete development of a tissue or organ- often refers to an inadequate or below normal number of cells
Two examples of hypoplasia + explanation
Klinefelter syndrome- set of symptoms that result from two or more X chromosomes in males- causes poorly functioning testicles and infertility.
Turner syndrome- women have partly missing X chromosome- symptoms include a short webbed neck, low set ears, short stature and swollen hands and feet. Ovaries don’t form properly
Two different types of progressive decreased growth - atrophy
Involution (physiological atrophy) and pathological atrophy
Involution definition
The shrinking or return of an organ to a former size, occurring due to normal stressors
What is involution characterised by at the cellular level?
Proteolysis of the basal lamina, leading to epithelial regression and apoptosis with accompanying stroll fibrosis. Reduction in cell number and reorganisation of stroll tissue leads to the reduction in the size of the organ
Example of involution + explained
Thymus involution
Thymus continues to grow between birth and puberty, then begins to atrophy- controlled by sex hormones. Eventually tissue becomes replaced by fat.
Pathological hypertrophy
Decrease in the size of organs due to an abnormal stressor
Different types of pathological decreased growth + examples
General- wasting in starvation and cachexia, tissue-specific such as osteoporosis and local atrophy through various causes.
Starvation atrophy explained
No diet, no nutrients, muscles and lipids and other macromolecules broken down to provide energy.
Cachexia definition + explained
Muscle wasting syndrome, caused by certain diseases. Commonly seen in AIDs and cancer. Causes ongoing muscle loss that is not entirely reversed with nutritional therapy.
Pathophysiology believes that inflammatory cytokines are released, inducing gene transcription
Osteoporosis explained
Bone atrophy- reduction in bone density due to the excessive rate of bone breakdown (over stimulated osteoclasts or poor acting osteoblasts). Makes the bones susceptible to breaking
