Organization Of The Body Flashcards
1
Q
What is the epithelium?
A
Epithelium is the lining of glands, the bowel, the skin and organs.
2
Q
Define atrophy.
A
Decrease in size of cells.
3
Q
Define hypertrophy.
A
Increase in size of cells.
4
Q
Define hyperplasia.
A
Increase in number of cells.
5
Q
Define dysplasia.
A
Change in shape of cells.
6
Q
Define metaplasia.
A
Replacement of one type of cell with another.
7
Q
Define neoplasia.
A
Abnormal growth of cells.
8
Q
Define necrosis.
A
Cellular death.
9
Q
Define apoptosis.
A
The programmed death of cells.
10
Q
What is a neoplasm?
A
A tumour
11
Q
What are epithelia?
A
Epithelia are layers of cells that have a minimal matrix, they regulate the passage of material between cells and provide those cells with strength, they are innervated at the base and they are absent of blood vessels.
12
Q
State the function of epithelia.
A
Lining epithelia regulates the passage of materials in and out the body. They also act as secretory cells and secrete bodily fluids.
13
Q
What are the three types of epithelia.
A
Surface, glandular and special.
14
Q
State the function of the exocrine glandular epithelia.
A
It regulates the ion concentration of epithelia.
15
Q
What are exocrine glands and state the 2 types.
A
Exocrine glands discharge products via ducts. There are simple and compound.
16
Q
Classify exocrine glands by morphology.
A
Tubular, branched tubular, coiled tubular acinar, branched acinar.
17
Q
Classify exocrine glands by secretion.
A
There are 3 types of secretion; merocrine, apocrine and holocrine. In merocrine (eccrine) secretion, exocytosis occurs where materials are expelled from a cell through the fusion of a vesicle with a cell membrane. In apocrine secretion, membrane bound vesicles are pinched off the apical portion of the cell e.g. sweat glands. In holocrine secretion, a rupture of secretory cells occurs. The cell disintegrates and releases its contents, mitotic divisions exist to replace cells e.g. sebaceous glands.
18
Q
What is the function of surface epithelium?
A
It covers exposed surfaces, acts as lining, it provides physical protection, sensation and controls permeability.
19
Q
What are the 8 types of surface epithelium? What do they feature and provide an example.
A
20
Q
What are the functions of stratified squamous epithelium?
A
Protection, the moist layer resists dehydration, thermoregulation and sensation.
21
Q
What is endothelium?
A
Endothelium is the lining of blood vessels and lymphatic vessels.
22
Q
What is mesothelium?
A
Mesothelium is the lining of the pleural and pericardial spaces.
23
Q
What is mesenchyme?
A
Mesenchyme is embryonic connective tissue that fills the space between organs.
24
Q
What type of epithelium is found in the salivary gland?
A
Stratified cuboidal epithelium
25
Where is stratified columnar epithelia found?
Salivary gland duct
26
What are the functions of pseudostratified columnar ciliated epithelial cells? Where are they found?
Pseudostratified columnar ciliated epithelial cells secrete mucus, trap particles, move mucus and make air clean, moist and warm. It is found in the trachea and the lining of the bronchus.
27
What are the functions of transitional epithelial cells? Where are they found?
Transitional epithelia permit distension (enlargement due to pressure). This is found in the ureter and bladder.
28
What is basement membrane?
Basement membrane is a matrix that anchors epithelial cells to underlying tissue.
29
How does proliferation occur in epithelia?
Proliferation occurs in epithelia by mitosis. Microtubules form, chromosomes duplicate and align at equator in metaphase, chromosomes pull apart and the cell divides. It is seen in the lower intestinal crypts. Vincristine arrests metaphase and prevents the formation of microtubules.
30
(SH)
31
What are the functions of muscle?
Movement of the body, manipulation of objects, propulsion of contents through organs and emptying the contents of organs.
32
What is the outer membrane (plasmalemma) of muscle called?
Sarcolemma
33
State the function of myoglobin.
Stores O2 and gives muscle colour.
34
What are the types of skeletal muscle cells?
Motor units, myoneural junctions
35
What is sarcoplasm?
The sarcoplasm is the cytoplasm of muscle cells excluding myofibrils.
36
What is the epimysium?
Epimysium is a thick layer of collagenous collective tissue that separates large bundles of muscle.
37
What is the sarcoplasmic reticulum?
The sarcoplasmic reticulum is the smooth endoplasmic reticulum of cells.
38
What is the perimysium?
The perimysium is a collagenous connective tissue that separates smaller bundles of muscles (fascicles).
39
What is a fascicle?
A fascicle is a bundle of muscles cells bound by perimysium.
40
What is the endomysium?
The endomysium is the thin layer of connective tissue that separates individual muscle cells.
41
Describe the organization of muscle in order of size.
Muscle, fascicle, muscle cell(fibre), myofibril, myofilaments.
42
What does syncytial mean?
Syncytial is descriptive of a syncytium which is a multinucleate mass of cytoplasm resulting from the fusion of cells. (as seen in individual muscle cells)
43
Describe the appearance of myofibrils.
A myofibril displays alternating bands of light and dark bands. The light bands (I bands) consist of thin filaments (actin) only. The dark bands (A bands) consist of thick (myosin) and thin filaments.
44
What is a sarcomere?
A sarcomere is the functional unit of a muscle, it's defined as the area between 2 consecutive z-discs.
45
What is a z-disc?
A z-disc is a dense thin membrane made up of special lattice-like proteins (α-actinin, desmin) present transversely.
46
What is a h-zone?
A h-zone is the lighter area in the middle of the A band, where the thin filaments do not reach. It consists of thick filaments only.
47
What is an m-line?
An m-line is a line that extends vertically down the middle of the A-band in the center of the H-zone.
48
State the function of tropomyosin.
Tropomyosin is a regulatory protein. In the resting state of a muscle, tropomyosin covers the myosin-binding sites on actin, preventing myosin from attaching to actin. (involved in cross-bridge cycle)
49
State the function of troponin.
Troponin C binds to Ca2+. Troponin I is inhibitory. Troponin T attaches to tropomyosin. (involved in cross-bridge cycle)
50
State the function of titin.
Titin is a protein that connects the z-line to the m-line in the sarcomere and contributes to the contraction of skeletal muscle. (largest protein in body)
51
State the function of nebulin.
Nebulin provides elasticity to the sarcomere.
52
What are the 2 binding sites on the molecule of myosin?
The binding site for actin and for ATPase
53
Where do tendons originate?
Epimysium
54
What is the difference between the positions of nuclei in skeletal muscle as opposed to cardiac muscle?
Nuclei are located centrally in cardiac muscle whereas they are located peripherally in skeletal muscle.
55
What are cardiocytes?
Cardiocytes are cardiac muscle cells. They contact each other at intercalated discs. They are bound by desmosomes and gap junctions.
56
State the function of intercalated discs in cardiac muscle.
Intercalated discs allow for coordinated contraction of the cardiac muscle for rhythmic beating.
57
What is the shape of smooth muscle characterised by?
Smooth muscle has long, slender and spindle shaped cells, called fusiform.
58
Differentiate between grey and white matter in the brain.
Grey matter contains cell bodies (neuron perikarya), dendrites and unmyelinated axons, while white matter contains myelinated axons. White matter is located in the inner regions in the brain but the outer region in the spinal cord. Grey matter processes information while white matter transmits signals.
59
What is soma?
Soma is a cell body.
60
What are dendrites and axons?
Dendrites receive signals and axons conduct signals away from cell bodies.
61
Describe neurotransmission between the presynaptic terminal and the postsynaptic region.
Action potentials reach the presynaptic terminal. Presynaptic membrane depolarization induces a brief opening of Ca2+ channels. Ca2+ influx promotes exocytosis of synaptic vesicles with the release of neurotransmitters (glutamate). After diffusing across the synaptic cleft, the neurotransmitter reacts with postsynaptic receptors and promotes postsynaptic membrane depolarization. Membrane retrieval occurs by coated vesicles in a process called endocytosis.
62
Differentiate between agonist and antagonist drugs, pertaining to neurotransmission.
Agonist drugs activate receptors like neurotransmitters. Antagonist drugs inhibit receptors and block neurotransmitters from binding to receptors.
63
How is myelin produced in the CNS?
Oligodendrocytes
64
How is myelin produced in the PNS?
Schwann cells
65
State curare's effect on neurotransmission and muscle.
Blocks nicotinic ACh receptor
Muscle weakness
66
State atropine's effect on neurotransmission and muscle.
Blocks muscarinic ACh receptor
Dilates pupils, increases heart rate
(It is used to reverse effects of pesticides.)
67
State botulinum toxin's effect on neurotransmission and muscle.
Blocks ACh release
Muscle weakness
68
State black widow venom's effect on neurotransmission and muscle.
Promotes ACh release
Continuous contraction
69
State organophosphate's (pesticides/nerve gas) effect on neurotransmission and muscle.
Blocks ACh release
Continuous contraction
70
Compare nerve-nerve synapses and NMJs.
NNSs are smaller with a narrower synaptic cleft. NNSs have a smooth postsynaptic membrane, with no folds. NNSs may be excitatory or inhibitory, while NMJs are excitatory only. Only ACh is a neurotransmitter in NMJs. Summation is needed in NNSs. Potential is lower in NNSs, always subthreshold.
The opposite is true for NMJs.
71
State the function and different types of neuroglia in the CNS.
Neuroglia protect neurons and help them function. Astrocytes, oligodendrocytes, ependymal cells, microglia.
72
State the function of astrocytes.
Astrocytes link neurons to blood vessels and so they contribute to the blood-brain barrier.
73
Differentiate oligodendrocytes and Schwann cells.
Oligodendrocytes-CNS, Schwann cells-PNS. Oligodendrocytes myelinate multiple axons simultaneously, while Schwann cells myelinate a single axon segment per cell. Oligodendrocytes provide poor support for axonal regeneration, opposite is true for Schwann cells. When injured, oligodendrocytes form glial scars, inhibiting regeneration, while Schwann cells form regeneration tubes for axon repair. Oligodendrocytes originate from neural tube cells while Schwann cells originate from neural crest cells.
74
What are the 2 types of neuroglial cells in the PNS? State their function.
Schwann cells myelinate fibers of the PNS, they also assist in the regeneration of damaged axons.
Satellite cells surround cell bodies in ganglia, they regulate the chemical environment of the neurons.
75
State the function of mesenchymal stem cells. List some characteristics.
To differentiate into other cells. They are multipotent and are obtained bone marrow.
76
State the function of fibroblasts.
To synthesise an extracellular matrix and to heal wounds.
77
State the function of adipocytes.
To store and metabolise fat.
78
State the function of macrophages (histiocytes).
Phagocytosis, innate immune cell
79
State the function of mast cells.
To release histamine, innate immune cell
80
Name the types of fibers in connective tissue.
Collagen, elastin, fibrillin
81
State the 3 classifications of collagen and the types of collagen found in them.
Fibril-forming: types 1,2,3
Network-forming: 4,7
Fibril-associated: 9,12
82
Collagen type I
Fibril-forming: found in bone, skin, tendon, muscles, cornea
and walls of blood vessels.
83
Collagen type II
Fibril-forming: found in cartilaginous tissues. Found in intervertebral disk, vitreous body and hyaline cartilage.
84
Collagen type III
Fibril-forming: found in distensible tissues, tissues that can expand due to pressure from within, fetal skin and blood vessels.
85
Collagen type IV
Network-forming: found in the basement membranes and
muscles.
86
Collagen type VII
Network-forming: found beneath stratified squamous epithelia, forms anchoring fibrils that link to the basement
membrane.
87
Collage type IX
Fibril-associated: found in cartilage, localised at intersections of cartilage fibres.
88
Collagen type XII
Fibril-associated: found tendons and ligaments.
89
What are chondroblasts?
Chondroblasts synthesis ground substance and matrix.
90
What are chondrocytes?
Chondrocytes are mature cells that make up cartilage, they are embedded in matrix.
91
Describe the process of chondrification.
Chondrification is the formation of cartilage.
Mesenchymal cells differentiate into chondroblasts. Chondroblasts proliferate and synthesis ground substance and fibrous extracellular matrix. Chondroblasts separate into lacunae. More divisions form clusters of chondrocytes or isogenous groups. The chondrocytes are then embedded into the extracellular matrix.
92
What is ossification?
Ossification is the process whereby cartilage is replaced by bone.
93
State the 2 methods of growth for cartilage.
Appositional - increase in width
Interstitial - increase in length
94
What type of cartilage is the ear and epiglottis made of?
Elastic cartilage
95
How does bone maintain the acid-base balance of blood?
Bone buffers blood against excessive pH changes by absorbing or releasing alkaline salts.
96
How does bone work as a detoxifier?
Bone can absorb and store heavy metals (Pb, Hg, Cd, Sr). These toxic substances replace Ca in the matrix.
97
Compare cortical and cancellous bone.
Cortical (compact) bone makes up 80% of skeletal mass, while cancellous (spongy) bone makes up the remaining 20%. Cortical bone is a dense protective shell, while cancellous is a rigid lattice designed for strength and the interstices are filled with marrow. Cortical bone is found around all bones ben, shafts and beneath the periosteum. Cancellous bone is found in vertebrae, flat bones and the end of long bones.
98
What are osteoprogenitor cells?
Osteoprogenitor cells are bone stem cells. They generate osteoblasts and osteocytes.
99
What are osteoblasts?
Osteoblasts are bone forming cells. (Contains lots of RERs for protein synthesis)
100
What are osteocytes?
Osteocytes are inactive osteoblasts. (Most abundant)
101
What are osteoclasts?
Osteoclasts cells are phagocytic, they digest bone cells using lysosomal proteolytic enzymes.
102
Describe the formation of bone.
Osteoblasts produce osteoid, which is an organic matrix composed of type I collagen. Osteoid becomes calcified, where Ca salts deposit into the osteoid. Osteoblasts release matrix vesicles rich in the enzyme alkaline phosphatase (AP). AP catalyses the formation of hydroxyapatite crystals by combining Ca2+ and PO43- ions. This gives bone its rigidity.
103
How is the process of bone formation hindered in rickets and chronic renal failure?
In rickets and chronic renal failure, there is inadequate calcium and phosphate ions in osteoid tissue and this slows mineralisation.
104
State the process whereby long bones grow.
Endochondral ossification
105
State the process whereby flat bones grow.
Intramembranous osssification
106
What is a diaphysis?
A diaphysis is the shaft of a bone.
107
What is an epiphysis?
An epiphysis is the expanded end of a bone.
108
What is a metaphysis?
A metaphysis is a flared portion between the diaphysis and the epiphysis.
109
What is an epiphyseal plate?
An epiphyseal plate is cartilage that separates epiphyseal and diaphyseal cavities.
110
What are alternative names for immature and mature bone?
Immature - woven bone
Mature - lamellar bone
111
Describe the process of ossification using the 6 zones.
Reserve cartilage zone: consists of chondrocytes.
Proliferation zone: chondrocytes undergo mitotic division.
Maturation zone: chondrocytes undergo hypertrophy.
Calcification zone: cartilage matrix calcifies.
Cartilage degeneration zone: chondrocytes degenerate.
Osteogenic zone: osteoblasts commence bone formation by depositing osteoid on exposed cartilage.
112
What happens when a bone is fractured?
At 6 hours, a blood clot is formed at the site. This is then replaced by collagen tissue. At 2 weeks, chondroblasts lay down cartilage, making a provisional callus. At 3 months, osteoblasts lay down woven bone, making a bony callus. The bony callus is then remodelled to lamellar bone.
113
Differentiate between the 2 types of ossification.
In intramembranous ossification, direct chondrocytes lay down bone and fractures are treated by internal fixation with screws/pins.
In endochondral ossification, cartilage is seen as a precursor, fractures are treated with plaster of Paris.
114
How does vitamin D regulate bone growth/loss?
Vitamin D promotes osteoblast differentiation.
115
How does growth hormone regulate bone growth/loss?
GH promotes osteoblast function.
116
How does calcitonin regulate bone growth/loss?
Calcitonin inhibits osteoclasts.
117
How does oestrogen regulate bone growth/loss?
Oestrogen inhibits osteoclasts.
118
How does cortisol regulate bone growth/loss?
Cortisol promotes apoptosis of osteoblasts.
119
How does parathyroid hormone regulate bone growth/loss?
PTH activates osteoclasts.
120
How does thyroid hormone regulate bone growth/loss?
TH activated osteoclasts.
121
How does vitamin A regulate bone growth/loss?
Vitamin A activates osteoclasts.
