Abnormalities of Growth

Question 1

Hypertrophy definition

Answer 1

Increase in cell size

Question 2

What sort of tissues does it occur in + example?

Answer 2

Permanent tissues such as cardiac and muscle cells

Question 3

What occurs in muscle hypertrophy?

Answer 3

Growth from adding sarcomeres as well as increase in non-contractile elements such as sarcoplasmic fluid

Question 4

Hyperplasia definition

Answer 4

Increase in a tissue, so cell growth coupled with proliferation

Question 5

What sort of tissues does it occur in + example?

Answer 5

renewing tissues, such as stem cells, skin epidermis (when abrasion occurs)
and red blood cells

Resting tissue- very limited, endocrine glands

Question 6

Neoplasia definition

Answer 6

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

Question 7

Difference between a tumour and cancer

Answer 7

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.

Question 8

neoplasia vs hyperplasia

Answer 8

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.

Question 9

Benign tumour growth

Answer 9

A mass of cells that lacks the ability to invade surrounding tissue so instead grow by expansion.

Question 10

Malignant tumour growth

Answer 10

Characterised by anaplasia, invasiveness and metastasis. They invade surrounding tissues and progressively get worse.

Question 11

Agenesis definition

Answer 11

failure of an organ to develop

Question 12

Example of agenesis

Answer 12

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

Question 13

What is bilateral renal agenesis?

Answer 13

both metal kidneys fail to develop during gestation.

Question 14

Hypoplasia definition

Answer 14

underdevelopment or incomplete development of a tissue or organ- often refers to an inadequate or below normal number of cells

Question 15

Two examples of hypoplasia + explanation

Answer 15

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

Question 16

Two different types of progressive decreased growth - atrophy

Answer 16

Involution (physiological atrophy) and pathological atrophy

Question 17

Involution definition

Answer 17

The shrinking or return of an organ to a former size, occurring due to normal stressors

Question 18

What is involution characterised by at the cellular level?

Answer 18

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

Question 19

Example of involution + explained

Answer 19

Thymus involution

Thymus continues to grow between birth and puberty, then begins to atrophy- controlled by sex hormones. Eventually tissue becomes replaced by fat.

Question 20

Pathological hypertrophy

Answer 20

Decrease in the size of organs due to an abnormal stressor

Question 21

Different types of pathological decreased growth + examples

Answer 21

General- wasting in starvation and cachexia, tissue-specific such as osteoporosis and local atrophy through various causes.

Question 22

Starvation atrophy explained

Answer 22

No diet, no nutrients, muscles and lipids and other macromolecules broken down to provide energy.

Question 23

Cachexia definition + explained

Answer 23

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

Question 24

Osteoporosis explained

Answer 24

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

Question 25

Different types of local atrophy

Answer 25

Disuse, ischaemic, neuropathic and idiopathic

Question 26

Disuse definition

Answer 26

Muscle of bone not being in use, perhaps in a cast so not used

Question 27

Disuse atrophy explained

Answer 27

Caused by mechanical unloading of muscle and this leads to reduced muscle mass without fibre attrition. Caused by changes to satellite cells and myonuclei.

Question 28

Ischaemia definition

Answer 28

Restriction of blood supply to tissues, causing a shortage of oxygen that is needed for cellular metabolism, causing the tissue to die.

Question 29

Example of ischemic atrophy + explained

Answer 29

Cerebral atrophy- loss of neurons and connections between them due to a stroke (sudden loss of blood to the brain)

Question 30

Neuropathy definition

Answer 30

Damage to nerves

Question 31

Neuropathic atrophy explained

Answer 31

Damage to the nerve the connects to a muscle

Question 32

poliomyelitis atrophy explained

Answer 32

Poliomyelitis is an acute infection caused by the polio virus, where the virus enters the central nervous system and damages the nerves controlling motor and autonomic function .

Question 33

Idiopathic definition

Answer 33

Relating to or denoting any disease of condition that Aries spontaneously or which the cause is unknown

Question 34

Example of an idiopathic atrophy + explain

Answer 34

Parkinson’s- death of midbrain dopaminergic neurons and presence of Lewy bodies

Characterised by cell death in the brain’s basal ganglia and the presence of Lewy bodies. The loss of neurons is accompanied by the dead of astrocytes and an increase in microglia. Symptoms include shaking, rigidity, slowness of movement and difficulty walking