Litir 1 - Tissue Epithelial

### Lecture Notes - Litir 1

Tha epithelial tissue is vascular and innervated, with a basement membrane.
Simple squamous epithelium is made of flat cells, found in lung alveoli and inner linings of blood vessels (endothelium).
Simple cuboidal epithelium has rounded nuclei, found in thyroid follicles (secretion) and kidney tubules (excretion).
Simple columnar epithelium has oval nuclei, found in the stomach (secretion) and intestines (absorption).
Simple columnar ciliated epithelium also has oval nuclei, and is found in the uterus and fallopian tubes for the transport of ova.
Pseudostratified columnar ciliated epithelium has cells of varying heights; nuclei are at different levels, and is found in respiratory systems for protection.
Stratified squamous epithelium (keratinized) is found in the skin for protection.
Stratified squamous epithelium (non-keratinized) is found in the oesophagus for protection.
Transitional epithelium is found in the urinary system (urinary bladder and ureter) and is distensible.
Glandular epithelium is exocrine (with ducts) or endocrine (without ducts).

### Lecture Notes - Litir 2

Connective tissue is vascular, with widely separated cells, containing matrix, fibers, and cells.
Connective tissue originates from mesoderm.
Types of connective tissue include blood (liquid), proper connective tissue (gelatinous), cartilage (rubbery), and bone (solid).
Ground substance (matrix) is a colorless, transparent, gel-like material.
Connective tissue fibers include white collagen fibers, which are thick, unbranched, and resist stretching, and yellow elastic fibers, which are thin, branched, and stretchable.
Reticular fibers are a type of collagen fiber, and are found in the basement membrane.
Connective tissue cells include fixed cells (fibroblasts, pericytes, adipocytes, mast cells) and transient cells (macrophages, plasma cells, neutrophils, eosinophils, basophils). Mesenchymal stem cells are undifferentiated mesenchymal cells.
Edema is an accumulation of excess fluid due to decreased venous blood flow, obstruction of lymphatic vessels, or increased capillary permeability.

### Lecture Notes - Litir 3

Bone is solid, collagen type I, and highly vascular.
Bone matrix consists of lamellae which contain organic collagen type I and inorganic calcium phosphate.
Major bone cells include osteogenic cells, osteoblasts, osteocytes, and osteoclasts.
Alkaline phosphatase is an enzyme involved in bone growth.
Bone tissue is composed of compact bone (osteons) and spongy bone (cancellous/trabeculae bone).
Compact bone contains haversian canals, while spongy bone lacks haversian systems and is found in the flat bones, ribs, and skull.

### Lecture Notes - Litir 4

Compare bone with cartilage, noting that bone is vascular and osteocytes cannot divide, while cartilage is non-vascular and chondrocytes can divide.
Bone development includes endochondral ossification (from hyaline cartilage) and intramembranous ossification (from membrane of mesenchymal tissue, for example flat bones).
Blood consists of plasma (55%) and blood cells (45%), including red blood cells (RBCs, 44%), white blood cells (WBCs, 1%), and platelets (less than 1%).

### Lecture Notes - Litir 5

Blood vessels have differing structures; arteries have thick walls and narrow lumens, while veins have thin walls and wide lumens.
Red blood cells (erythrocytes) lack nuclei and contain hemoglobin; males have 5-5.5 million, and females have 4.5-5 million, per mm³.
Hemoglobin carries oxygen. Hematocrit measures the proportion of RBCs in the blood.
Anemia is characterized by a low RBC count, while polycythemia is associated with a high RBC count.
Leukocytes (white blood cells) are involved in the immune response.

### Lecture Note - Litir 6

Granular leucocytes - include neutrophils, basophils, and eosinophils.
Neutrophils are phagocytic; neutrophilia indicates an increase in neutrophil count, and neutropenia indicates a decrease.
Basophils release histamine and are involved in allergic reactions. Eosinophils are involved in parasitic infections and allergic reactions.
Non-granular leucocytes - include lymphocytes and monocytes. Lymphocytes play a role in cellular and humoral immunity.

### Lecture Note - Litir 7

Monocytes are highly phagocytic cells that transform into macrophages in tissues.
Platelets (thrombocytes) are cell fragments, derived from megakaryocytes, involved in the clotting process.

### Lecture Note - Litir 8

Nervous tissue includes nerve cells (neurons) and neuroglia. Neurons conduct nerve impulses. Neuroglia provide support and protection to neurons. Neurones don't divide.
Neurons have a cell body (soma), dendrites, and an axon; axons are often myelinated.
Different types of neurons, classified by function, include motor neurons, interneurons, and sensory neurons.
Myelin is a fatty substance that accelerates nerve impulse conduction.

### Lecture Note - Litir 9

Cell types are classified into neurons (motor, inter, sensor) and neuroglia.
Myelin accelerates nerve impulse conduction.
Neurons don't divide (no centrioles), while neuroglia do divide.

### Lecture Note - Litir 10

Atrophy is the shrinking of a tissue or organ, often a result of disease or illness.
Neuroglia include astrocytes, oligodendrocytes, microglia, and ependymal cells. Astrocytes provide metabolic support and regulate the extracellular environment around neurons.
Myasthenia gravis is an autoimmune disorder that weakens skeletal muscles.

### Lecture Note - Litir 11

Plant cells have cell walls, vacuoles, and chloroplasts; the cell wall is made of cellulose.
Plant tissues are divided into ground tissue, vascular tissue. Plant tissue consists of both ground and vascular tissues.
Xylem transports water and nutrients, and phloem transports sugars (photosynthetic products from leaves).
Parenchyma cells are thin-walled cells used in storage.
Sclerenchyma cells are thick-walled cells used for support, often dead.
Collenchyma cells are elongated cells found in supports.
Aerenchyma is a ground tissue whose cells have air spaces, enabling buoyancy.
Plants have an apical meristem (for primary growth) and a lateral meristem (for secondary growth)

### Lecture Note - Litir 12

Plant tissues are divided into dermal tissue, vascular tissue, and ground tissue.
Dermal tissue—the outer layer of the plant—protects the plant, and is made up of cuticle and stomata for gaseous exchange.
Vascular tissue, which comprises xylem and phloem, transports water and minerals (xylem) and nutrients (phloem) throughout the plant.
Ground tissue, which includes parenchyma, collenchyma, and sclerenchyma tissue types, has various functions. Aerenchyma cells contain air spaces for support and buoyancy in aquatic plants.
Active transport is used to move minerals into cells while osmosis is used to move water.

### Lecture Note - Litir 13

Vascular tissue transports water and minerals while phloem transports sugars. These are transported out of the plant by active transport.
A stele is a vascular cylinder located in the roots of seed plants. A stele is made of xylem and phloem.

### Lecture Note - Litir 14

Parts of a plant include leaves, stems, and flower. The leaves of the plant contain vascular tissue, and their stomata regulate gas exchange.
A flower has parts like sepals, petals, stamens (male parts), and pistil (female parts). Stamens have filaments and anthers which produce pollen grains.

### Lecture Note - Litir 15

The digestive system comprises mucosa, submucosa, muscularis, and serosa.
Enteric plexus nerves are located in the submucosal and myenteric layers. The digestive system has both endocrine and exocrine glands.
Parietal cells secrete hydrochloric acid and intrinsic factor, while chief cells secrete pepsinogen.
Gastritis, an inflammation of the stomach lining, can follow from infections or use of non-steroidal anti-inflammatory drugs (NSAIDs).

### Lecture Note - Litir 16

The small intestine's surface area is increased by folds, villi, and microvilli, enhancing absorption.
The liver is the largest internal organ, producing bile, detoxifying substances, and producing blood clotting factors.
Hepatocytes are liver cells that filter blood-borne toxins, regulate blood glucose, and process nutrients.
Bile is produced by hepatocytes and stored in the gallbladder, released into the duodenum to aid fat emulsification.
The pancreas produces digestive enzymes and hormones such as insulin and glucagon.
Steatosis (fatty liver) is a condition of fat accumulation in the liver, and fibrosis is the formation of fibrous tissue in an organ.

### Lecture Note - Litir 17

The large intestine consists of the ascending colon, transverse colon, descending colon, and sigmoid colon. Inflammation of the large intestine is described as acute or chronic, with different exudates.

### Lecture Note - Litir 18

The cardiovascular system consists of the heart, blood vessels (arteries, veins, capillaries), and blood.
The cardiovascular system pumps blood through the body, supplying oxygen and nutrients to tissues and removing waste products.
The superior and inferior vena cava carry de-oxygenated blood back to the heart.
The aorta is the main artery that carries oxygenated blood from the heart to the body.
Valves prevent backflow of blood. Blood exchange oxygen for carbon dioxide in the lungs.

### Lecture Note - Litir 19

The lymphatic system is a one-way system for lymph fluid collected from tissues.
Fluid from tissues is collected into capillaries and vessels that drain to the superior vena cava.
Elephantiasis is caused by parasitic infection blocking the lymph flow, resulting in chronic edema.
Thrombosis involves the formation of a blood clot, and is often associated with endothelial injury or hypercoagulability.

### Lecture Note - Litir 20

The respiratory system includes the trachea (windpipe), lungs (divided into lobes), and alveoli (air sacs).
Type I pneumocytes are squamous cells forming the blood-air barrier, whereas Type II pneumocytes secrete surfactant to prevent lung collapse.
Pneumonia involves inflammation of the alveoli. Emphysema is a chronic disease characterised by permanent enlargement of alveoli.
Hypoxia is not enough oxygen in tissues.

### Lecture Note - Litir 21

The kidneys (approximately 125-170g) are involved in filtering the blood and forming urine. Each kidney contains millions of nephrons, its functional unit.
Nephrons involve glomerular filtration, tubular reabsorption, and secretion.
Bowman's capsule and its associated structures play a role in filtering blood.
Podocytes form a filtration barrier; mesangial cells support glomerular capillaries.

### Lecture Note - Litir 22

Glomerular filtration rate (GFR) is the rate at which fluid is filtered out of the capillaries in the glomerulus.
Proximal convoluted tubule performs reabsorption of materials like glucose and amino acids into the blood, and secretion of wastes.
The distal convoluted tubule is involved in the regulation of the potassium/sodium balance.
The collecting duct is the final part of urine formation that transports urine to the renal pelvis for excretion.
GFR (Glomerular filtration rate) is influenced by creatinine levels, as creatinine is a waste product of muscle metabolism.

### Lecture Note - Litir 23

The male reproductive system includes the testes, epididymis, vas deferens, seminal vesicles, and prostate gland.
Spermatogenesis occurs in the testes, involving Sertoli cells and Leydig cells for promoting sperm production and testosterone secretion.
Cryptorchidism is the failure of testes to descend into the scrotum.

### Lecture Note - Litir 24

The female reproductive system involves the ovaries as the main endocrine and exocrine site producing estrogen and progesterone.
The ovaries contain follicles where the egg (ovum) matures and are released during ovulation.

### Lecture Note - Litir 25

Ovulation is the process of releasing a mature egg (ovum) from an ovarian follicle.
Cervical cancer is associated with certain viral infections and often involves cancerous epithelial cells.
Breast cancer is a common cancer among women, often involving epithelial cell malignancies that can spread. Certain forms of breast cancer display fibrosis.
Benign tumors grow slowly and have a well-defined capsule, often without metastasis.

### Lecture Note - Litir 26

Skin is categorized as thick (palms and soles) and thin skin (everywhere else).
Thick skin lacks hair follicles and sebaceous glands but contains Keratinocytes.
Thin skin has hair follicles and sebaceous glands and contains melanocytes, among other cell types.
Keratinocytes produce the protein keratin to provide structural protection.
Melanocytes produce melanin that protects against UV light.

### Lecture Note - Litir 27

Wound healing involves inflammatory, proliferative, and maturation phases, often characterized by intention and scarring.
Necrosis involves cell swelling and lysis, triggering an inflammatory response, while apoptosis is programmed cell death.

### Lecture Note - Litir 28

Apoptosis and cancer are related; specific genes such as E6, HPV, and p53 can lead to inactivation of apoptosis pathways. This can lead to cancerous situations as cells avoid apoptosis.