Tissues Of The Body Flashcards
To cover all aspects of Tissues of the Body for ESA 1 Note: You will still need to go through histological slides and be able to name different parts I take no responsibility for any of the flashcards featured here...mistakes/shit happens.
1
Q
Define epithelia.
A
Epithelia are sheets of contigous tissue of varying embryonic origin that cover the external surfaces and line the internal surfaces of the body.
2
Q
An increase of muscle mass from work performed against load results in what? What is this described as?
A
More contractile proteins, increase in fibre diameter - Hypertrophy
3
Q
Describe keratinocyte differentiation
A
1) Keratinocyte mitosis occurs in BASAL layer 2) Daughter keratinocytes move into prickle cell layer where terminal differentiation occurs meaning the cells can no longer divide 3) Then in the granular layer cells lose plasma membrane and become corneocytes 4) FInally in the stratum corneum they are flattened corneocytes
4
Q
Cardiac muscle cannot be regenerated, what happens instead?
A
Fibroblasts invade, divide and lay down scar tissue
5
Q
How does calcium allow for the binding of myosin to actin?
A
-Increased amounts of calcium bind to the TnC part of troponin -Conformational change moves tropomyosin away from the actin binding site -This displacement allows for the binding of myosin to the actin site
5
Q
Describe the mechanism of innervation of muscle and excitation contraction coupling. (6 points)
A
-Action potential arrives at the pre synaptic neurone causing influx of Ca2+ -Causes vesicles containing acetylcholine to fuse with membrane and release Ach -Binds to nicotinic receptors on the motor end plate -Binding leads to depolarisation of the sarcolemma by an influx of sodium -Proteins in T tubule change conformation causing calcium to be released from the terminal cisternae into the sarcoplasm -Ca2+ binds to Tnc on troponin casuing contraction
5
Q
Define the term “limit of resolution”
A
Limit of resolution is the minimum distance that two objects can be distinguished at.
6
Q
Describe the two different types of bone.
A
-Compact (dense) bone made up of vertical osteons with horizontal Volkmann’s canals and vertical Haversian canals -Cancellous (spongy) bone - Meshwork of trabeculae filled in with marrow
7
Q
Describe the process of endochondral ossification
A
-Cartilage is reabsorbed and replaced with bone (e.g. long bones) -Begins at the primary centre in the shaft (diaphysis) and later at each end (epiphysis – secondary centre) -Growth in length is at epiphyseal growth plates
7
Q
Describe the process of intramembranous ossification
A
-Begins as highly vascularised loose connective tissue. -Mesenchymal cells differentiate into osteoblasts surrounded by collagen fibres and ground substance. -Osteoblasts secrete uncalcified matrix (osteoid) and then become osteocytes
8
Q
How can skeletal muscle be repaired?
A
-Tissue regenerates by the mitotic activity of satellite cells which fuse with muscle cells to increase mass
9
Q
Give two examples of cholinergic transmitters of the post ganglionic nerve fibres of the sympathetic nervous system.
A
-Perspiration -Ejaculation
10
Q
Describe what a muscle is made of, with each component in order of size?
A
-Fascicles -Muscle fibres (cells) -Myofibrils -Myofilaments (actin and myosin)
11
Q
Give some examples, other than blood, of loose connective tissue.
A
Forms the septa (walls) and trabeculae (rods) that make up the framework inside organs and adipose tissue.
12
Q
Describe the histological structure of tendons.
A
-Collagen fibres interspersed with flattened fibroblasts in bundles -> fascicles -Fasiciles have endotendineum (loose CT) inside and held together by peritendineum. A fibrous sheath surrounds the whole tendon
13
Q
Describe the cellular processes involved in bone repair following a fracture
A
-Matrix is destroyed - bone cells adjoining the fracture will die -Inflammatory cells invade and form a pre-callus which contains a blood clot (haematoma) and fibrous tissue -Osteocallus of primary bone is made which is then calcified to secondary -Tendons pull and pressure the bone until it matches the contours of the surrounding bone until it fully heals
14
Q
How many days does it take for skin to be renewed?
A
28 Days
15
Q
How many days does it take for small intestine epithelia to be renewed?
A
4-6 Days
16
Q
In the CNS what maintains the myelin coating?
A
Glial cells called oligodendrocytes
17
Q
How does demyelination relate to a slowing of conduction velocity?
A
The impulse can no longer jump from Node of Ranvier by saltatory conduction and therefore cannot be propagated as quickly meaning the impulse moves slower
18
Q
In rare cases some post ganglionic transmitters of the sympathetic nervous system are not noradrenergic, what transmitter are they?
A
Cholinergic transmitters
19
Q
In general terms outline the process of haemopoiesis
A
-Proliferation: Starting with a stem cell, the cell divides into two. One to replace the original stem cell (self-renewal) and one that differentiates. -Differentiation of haemopoietic progenitor (under influence of cytokine) to form either a myeloid blast (RBC, WBC, platelets) or a lymphoid blast (immunoresponse cells)
20
Q
In the parasympathetic nervous system what type of receptors do the post ganglionic neurones express?
A
Nicotinic receptors
21
Q
List the 4 types of skin appendage
A
-Hair Follicles -Nails -Sebaceous glands -Eccrine and apocrine sweat glands
21
In the parasympathetic nervous system what type of transmitter is used in the post ganglionic nerve fibre?
Cholinergic transmitters
22
In the parasympathetic nervous system what type of transmitter is used in the pre ganglionic nerve fibre?
Cholinergic transmitters
23
In the sympathetic nervous system what type of receptors do the post ganglionic neurones express?
Nicotinic receptors
25
In the sympathetic nervous system what type of transmitter is used in the pre ganglionic nerve fibre?
Cholinergic transmitters
26
In the sympathetic nervous system what type of transmitter (mainly) is used in the post ganglionic nerve fibre?
Noradrenergic transmitters
27
Name the five cellular components of the innate immunity system and describe what each of them do?
-Macrophages and Monocytes – phagocytosis and antigen presentation to lymphocytes. Phagocytosis is enchanced by the coating of antibodies or complement to render it recognisable as foreign (opsonisation). -Neutrophils – Phagocytic and anti-bacterial -Eosinophils – Anti-parasite and allergic response -Basophils & Mast Cells – Allergic response -Natural Killer Cells – Recognise and kill abnormal cells, e.g. tumours
28
Name the seven humoral components of the innate immunity system and describe what each of them do?
-Transferrin/Lactoferrin – deprive microorganisms of iron -Interferons – Inhibit viral replication -Lysozyme – Breaks down peptidoglycan in bacterial cell walls -Antimicrobial peptides -Fibronectin – opsonises bacteria and promotes their phagocytosis -Complement – Cause destruction of microorganisms directly or with the help of phagocytic cells -TNF-α - Suppresses viral replication and activates phagocytes
28
Name the three humoral components of the adaptive immunity system and describe what each of them do?
-Cytokines – Promote the differentiation and proliferation of lymphocytes -Perforin – Released by T killer cells and destroy cell walls -Antibodies – Protect host by neutralisation (prevents binding to epithelia), opsonisation and complement activation (enhances opsonisation and lysis)
30
Name the two cellular components of the adaptive immunity system and describe what each of them do?
-T cells: +T Helper – Become activated when CD4 binds to a specific antigen on the MHC/antigen complex of an APC (antigen presenting cells). Once activated, it clones itself to form active T-helper cells and T-memory cells. +T Killer – Releases perforin when cell is already infected -B Cells – Divide to form plasma cells and memory cells when activated by T-helper ells and release cytokines. Plasma cells produce specific immunoglobulin for non-self antigen.
31
What 5 cell constituents make up the dermis?
-Fibroblasts -Blood vessels -Lymphatic vessels -Mast Cells -Nerves
31
Name two places in the body where you could find dense regular connective tissue?
-Ligaments -Tendons
33
Outline the 5 stages of the sliding filament model of muscle contraction, starting with attachment.
-Attachment of the myosin head to the actin molecule -Release of the myosin head when ATP binds -Cocking of the myosin head due to hydrolysis of ATP -Force generation as the myosin weakly binds and the phosphate is released leading to the power stroke -Reattachment of the myosin head to the actin
33
The autonomic nervous system is made up of which two neurones?
Pre-ganglionic and post-ganglionic
34
What are entrapped chondroblasts known as?
Chondrocytes
35
What are fascicles made of?
Muscle fibres
36
What are fibroblasts?
Synthesise and maintain extra-cellular materials. Synthesise collagen, elastic and reticular fibres and ground substance.
38
What are ligaments made up of?
Dense regular connective tissue: -Collagen fibres interspersed with fibroblasts -Elastic ligaments - mainly elastin.
39
What are muscle fibres made of?
Myofibrils
40
What are mast cells?
Near blood vessels containing granules (histamine and heparin). They release pharmacologically active molecules.
41
What are neurones with multiple dendrites known as?
Multi-polar
42
What are neurones with one axon and one dendrite known as? Where are they usually found?
Bi-polar neurones usually found in the retina of the eye
43
What are neurones with one axon only known as? Give an example of one type.
Unipolar - the primary sensory neurone
44
What are the 4 main features of the perikaryon?
-Nucleus -Nucleolus -Nissl substance (aggregation of RER) -Dendrite
45
What are the 4 main functions of skin?
-Barrier -Sensation -Thermoregulation -Psychosexual communication
46
What are the 4 regions of the epidermis is descending depth?
Stratum Corneum Granular Layer Prickle Cell Layer Basal Layer (SGPB)
47
What are the 4 types of tissue classification?
-Muscle -Epithelial -Connective -Nervous
48
What are the 5 layers of stomach?
-Epithelium -Gastric Mucosa -Muscularis Mucosa -Submucosa -Muscularis Externae
49
What are the 6 layers of the oesophagus?
-Epithelium -Lamina Propria -Muscularis Mucosa -Submucosa -Muscularis Externa -Adventitia
50
What are the 5 types of white blood cells that circulate in the blood and lymphatic system? What type of nucleus does each have?
-Neutrophils (Multi-lobed nucleus) -Eosinophils (Bi-lobed) -Monocytes (Kidney shaped) -Basophils (Bi- or Tri-lobed) -Lymphocytes (Deep staining)
51
What are the benefits of smooth muscle?
-Contraction is more sustained -Contraction requires less ATP -Capable of being stretched
52
What are the components of the extracellular matrix in the dermis?
-Ground Substance -Fibres (Type 1 Collagen and Elastin)
52
What are the features of innate immunity which make it different to adaptive immunity?
-Present from birth -Non-specific -No memory -Not enhanced by secondary exposure
53
What are the features of Purkinje fibres?
-Abundant glycogen -Sparse myofilaments -Extensive gap junction sites -Rapid conduction of action potentials
55
What are the four layers of the ailmentary tract?
-Mucosa -Submucosa -Muscularis externa -Serosa
56
What are the gaps between Schwann cells called?
Nodes of Ranvier
57
What are the main features of mucous connective tissue? Where is it found?
-Large stellate fibroblasts (which fuse with similar adjacent cells), few macrophages and lymphocytes and soft ground substance full of hylauronic acid -Loose connective tissue -Only found in the umbilical cord and subdermal CT of the embryo.
58
What are the main functions of bone?
-Support -Protection -Mineral storage -Haemopoiesis.
59
What are the meninges?
The system of membranes which envelops the central nervous system
60
What are the relative sizes of the pre and post ganglionic nerve fibres in the parasympathetic nervous system?
Long pre-ganglionic and short post-ganglionic
61
What are the meninges?
The system of membranes which envelops the central nervous system
62
What are the three histological forms of muscle?
-Skeletal -Cardiac -Smooth
62
What are the relative sizes of the pre and post ganglionic nerve fibres in the sympathetic nervous system?
Short pre-ganglionic and long post-ganglionic
63
What are the three layers of meninges in increasing depth?
-Dura mater -Arachnoid -Pia mater
64
What are the three layers of meninges in increasing depth?
-Dura mater -Arachnoid -Pia mater
66
What are the three major types of cartilage?
-Hyaline -Elastic -Fibrocartilage
67
What are the two remnants of the hyaline cartilage (that made up the foetal skeleton) in the child?
-Growth plates -Articular cartilage
68
What are the two colours of marrow and what is their respective function?
-Red: red blood cell synthesis -Yellow: contains adipose tissue
69
What are the two types of ossification called? What do they give rise to?
-Intramembranous - flat bones created from loose connective tissue/mesenchyme -Endochondral - most skeletal bones, made from the hyaline cartilage of foetus
70
What can a smear be used for?
-Cervix -Buccal cavity
71
What can curettage be used for?
-Testing endometrial lining of uterus
72
What can direct incision be used for?
-Skin -Mouth -Larynx
73
What can endoscopic methods be used for?
-Lung -Intestine -Bladder
74
What can needle methods be used for?
-Brain -Breast -Liver -Kidney -Muscle
74
What can transvascular methods be used for?
-Heart -Liver
76
What causes differentiation to platelet cells?
Thrombopoietin
77
What causes differentiation to red blood cells?
Erythropoietin
78
What do melanocytes produce?
Melanin N.B. More melanin production leads to darker skin - not more melanocytes
79
What do many fascicles make up?
Muscles
80
What do serous membranes consist of?
-Simple, squamous epithelium -Connective tissue
80
What do myofilaments make up?
Myofibrils
81
What does a mucous membrane consist of?
-Epithelium -Lamina propria -Muscularis mucosa
83
What gives elastic fibres their ability to stretch?
High lysine content
84
What is a gland described as if it's ducts branch?
Complex/compound
85
What happens to bilirubin after it reacts with glucuronic acid?
-It is excreted into the bile -Bile goes through the gall bladder into the intestines where the bilirubin is changed into a variety of pigments (importantly stercobilin and urobilinogen) -Stercobilin excreted in the feces -Urobilinogen excreted via the kidneys
86
What is a gland?
An epithelial cell or collection of epithelial cells specialised for secretion
87
What is an endocrine gland?
A ductless gland which secretes directly into the blood
88
What is an exocrine gland?
A gland with ducts
89
What is another name for sensory neurones? What is their function?
Afferent neurones carry impulses to the central nervous system
89
What is another name for motor neurones? What is their function?
Efferent neurones carry impulses away from the central nervous system
91
What is areolar connective tissue made up of?
-Fibroblasts -Macrophages -Some mast cells -Collagen fibres are the most abundant -Elastin fibres also present.
92
What is cartilage made up of?
-Organic substances -Mesenchymal cells -Collagen type I fibres -Ground substance (protein, glycoprotein, glycosaminoglycans, lipids and water)
93
What is confocal microscopy?
Labelling of a tissue with multiple probes to produce a 3D render
94
What is connective tissue?
A tissue of mesodermal origin that consists of cells and protein fibers embedded in a chiefly carbohydrate ground substance
95
What is contained in mucous?
Mucins (high glycosylated polypeptides) which stain badly in H&E
96
What is Dark Field microscopy and why is it used?
Don't include the unscattered light from beam so it can be used to view live and unstained samples
97
What is erythropoiesis controlled by?
Partial pressure of O2 - if it's low it stimulates increase in erythropoietin
98
What is ground substance made up of?
-Glycosaminoglycans (GAGs) -Proteoglycans -Glycoproteins.
99
What is histology?
The study of the structures of tissues by means of special staining techniques combines with light and electron microscopy
100
What is haem broken down to? Where is this done?
Bilirubin in the reticuloendothelial cells of the liver, spleen, and bone marrow.
102
What is it called when more muscle is created than destroyed?
Hypertrophy
103
What is PAS and what does it stain?
Periodic Acid-Schiff stains carbohydrates and glycoproteins magneta
104
What is it called when more muscle is destroyed than created?
Atrophy
105
What is Phase Contrast and why is it used?
The interference effects of combining two light waves to enhance the image of unstained cells
106
What is the basement membrane?
The thin, flexible, acellular layer between the epithelial tissue and connective tissue
106
What is the benefit for a tendon of having dense regular connective tissue?
Fibre bundles orientated in parallel to provide maximum tensile strength which means huge strength in one direction
108
What is the benefit of glycosylation and where does it occur?
Branching sugars are added in the golgi and are responsible for interactions: -Inhibition -Communication -Adhesion
108
What is the benefit for the skin of havind dense irregular connective tissue?
Has Interwoven bundles of collagen which counteracts multi-directional forces
110
What is the benefit of the rapid conduction of action potentials down Purkinje fibres?
Enables the ventricles to contract in a synchronous manner
111
What is the definition of the term biopsy?
The removal of a small part of an organ for microscopic examination
112
What is the cartilage often surrounded by? What is this made up of?
Perichondrium (dense irregular connective tissue) made up of: -Outer Fibrous layer -Inner cellular (chondrogenic) layer
113
What is the difference if the periosteum is still intact when osteoclasts and macrophages during bone repair?
Formation of a pro callus (instead of pre callus) which is more fibrous
114
What is the foetal skeleton made up of?
Hyaline cartilage
116
What is the function of astrocytes? Where are they found?
Astrocytes are found in the blood brain barrier of the CNS and assist in the transfer of nutrients/waste
116
What is the function of basophils?
Mediate acute inflammatory reactions using heparin and histamine
117
What is the function of erythrocytes?
Carries O2 to tissues and CO2 to the lungs
117
What is the function of eosinophils and neutrophils?
Phagocytosis
119
What is the function of gap junctions?
Electrical coupling
120
What is the function of Langerhans cells?
Specialised to present antigens to T lymphocytes to mediate immune response
121
What is the function of lymphocytes?
-B Cells -T Cells
122
What is the function of oligodendrocytes? Where are they found?
Maintenance of the myelin sheath in the CNS
123
What is the function of microglia? Where are they found?
The microglia are important in immune and inflammatory responses in both the CNS and PNS
124
What is the function of monocytes?
-Migrate to become macrophages in many organs of the body -Capable of phagocytosis and interact with T cells
125
What is the function of Purkinje fibres?
They transmit action potentials to the ventricles from the atrioventricular node
126
What is the function of platelets?
- Clotting cascade - Adhere to damaged cells walls and aggregate together.
127
What is the function of reticular cells?
Direct the T and B lymphocytes to specific regions with the lymphatic tissues
128
What is the function of satellite cells?
Physical support of peripheral neurones
130
What is the function of the basement membrane?
-Provides surface for epithelia to adhere to -Cellular and molecular filter -Penetration into it gives an indication of cancer prognosis
131
What is the glycocalyx?
The cell ‘coat’ made up of oligosaccharide and polysaccharide side chains on the outside of the plasma membrane.
131
What is the function of the chondroblasts?
Secrete the matrix which entraps the cells
132
What is the hardness and rigidity of bone due to?
The interaction between collagen and inorganic salts
134
What is the main histological difference between ligaments and tendons?
In ligaments collagen is less regularly arranged than in tendons.
135
What is the main histological difference between loose and dense connective tissue? Why?
-Dense CT has close packing of fibres with fewer cells and less ground substance. This allows it to achieve mechanical support and transmit forces
136
What is the main type of collagen in hyaline and elastic cartilage? Why?
Type II Collagen for firm and flexible support
136
What is the main type of collagen in fibrocartilage? Why?
Type I Collagen (in bundles) for mechanical strength and rigidity and Type II Collagen
138
What is the meaning of the word tissue?
A collection of cells specialised for a particular function
139
What is the name for the nerve cell body?
Perikaryon
140
What is the overall function of the parasympathetic nervous system?
-Relaxed state -Reduced heart rate -Increased digestion -Increased bodily functions -Increased sleep
141
What is the overall function of the sympathetic nervous system?
-Fight/flight/fright -Diversion of blood to muscles -Increase in heart rate -Increase in blood pressure -Reduced blood flow to skin and GIT
142
What is the purpose of ground substance?
-Acts as a lubricant -Barrier to pathogens
143
What is the sleeve of Schwann cells surrounding peripheral nerves called?
Neurolemma
144
What is the structure of erythrocytes?
- Biconcave disc - 4 globin chains (2α & 2β) - Each molecule carries a haem
145
What is the structure of platelets?
- Small round blue particles - Produced by megakaryocytes in the bone marrow - Cytoplasm contains α (fibrinogen and Von Willebrand’s factor) and dense (ADP and Ca2+) granules
146
What is the structure of reticular cells?
Synthesise reticular fibres and surround them with cytoplasm
147
What is the thick filament called?
Myosin
148
What is the thin filament called?
Actin
149
What is the transit time of a keratinocyte from basal layer to stratum corneum during keratinocyte differentiation?
30-40 days
150
What is transepithelial transport?
When a molecule is too large to be taken though a membrane it is endocytosed into a vesicle and then exocytosed
151
What metabolic changes accompany hypertrophy?
-Increased enzyme activity for glycolysis -Increased mitochondria, -Increased stored glycogen -Increased blood flow
152
What parts of a tissue does H&E stain?
-Haematoxylin stains acidic components in the nucleus purple/blue -Eosin stains alkaline components in the cytoplasm pink
153
What shape are the cells of smooth muscle?
Spindle-shaped (fusiform)
154
What three types of cells are found in bone?
-Osteoblasts – synthesise organic bits of cells, make bone + produce osteoid matrix. -Osteocytes – found in the lacunae cavities, maintaining bone and are formed when osteoblasts are entombed -Osteoclasts – large multinucleated cells from monocytes that digest bone.
155
What two components make up the extracellular matrix?
Fibers and ground substance
156
What type of connective tissue is a nerve fascicle surrounded by?
Perineurium
157
What type of connective tissue is a single axon cell surrounded by?
Endoneurium
158
What type of connective tissue is an entire nerve surrounded by?
Epineurium
159
What type of connective tissue is blood?
Loose
160
What type of muscle has no sarcomeres or T Tubules?
Smooth muscle
161
What type of neurotransmitter do excitatory neurones release?
Release glutamate/aspartate neurotransmitter
162
What type of neurotransmitter do inhibitory neurones release?
Release of glycine/GABA neurotransmitter
163
What type of tissue is adipose tissue?
Loose connective tissue
164
What type of tissue is reticular tissue? Where is it found?
Loose connective tissue found in: -Liver -Kidney -Spleen -Lymph nodes -Bone marrow
165
Where are Langerhans cells found?
Prickle cell layer of the epidermis
166
Where are melanocytes found?
Basal cell layer of epidermis
167
Where can elastic cartilage be found?
-Pinna of ear -Epiglottis -Auditory tubes
168
Where can endocrine glands be found?
-Thyroid -Pancreas -Adrenal -Parathyroid
170
Where can exocrine glands be found?
-Goblet cells (unicellular glands) in Jejunum -Submandibular -Parotid -Pancreas
170
Where can fibrocartilage be found?
-Intervertebral discs -Menisci -Pubic symphysis
172
Where can hyaline cartilage be found?
-Respiratory passageways -Articulating surfaces of long bones -Anterior ends of the ribs -Foetal skeleton
173
Where can reticular fibres be found?
-Form a delicate network around smooth muscle cells, certain epithelial cells, blood vessels, adipocytes and nerve fibres -Make the structural framework around certain organs such as the liver, spleen, bone marrow and lymphoid organs.
174
Where can the protein elastin found?
Dermis of the skin
174
Where do skeletal muscle fibres interdigitate with tendon collagen bundles?
Myotendinous junction
176
Where is areolar connective tissue found? What type of connective tissue is it?
-Deep under the skin -Submucosa -Below the mesothelium of the peritoneum -With adventitia of blood vessels -Surrounding the parenchyma of glands Loose connective tissue
177
Where is bilirubin transported to? What happens to it while there?
Liver reacts bilirubin with a solubilizing sugar called glucuronic acid.
178
Where is the epidermal basement membrane located?
Occurs at the dermo-epidermal junction below the basal layer of the epidermis
179
Which areas in the body are simple squamous epithelia located?
-Loop of Henle -Bowman's capsule of Kidney -Mesothelium -Endothelium -Alveoli
180
Which areas of the body are keratinised stratified squamous epithelia located?
-Skin
181
Which areas of the body are non-keratinised stratified squamous epithelia located?
-Buccal cavity -Vagina -Anus -Oesophagus -Surface of cornea
182
Which areas of the body are simple columnar epithelia located?
-Lining of the stomach -Small intestine -Uterus -Oviducts -Gallbladder -Ductuli Efferents of testis
183
Which areas of the body are simple cuboidal epithelia located?
-Surface of the ovary as a barrier -Thyroid follicles -Kidney tubules
184
Which areas of the body are simple pseudostratified epithelia located?
-Lining of nasal cavity -Trachea -Bronchi -Eustachian tube -Epididymis
185
Which areas of the body are stratified transitional epithelia located?
Urinary bits: -Ureters -Bladder -Calyces of kidney
186
Which connective tissue surrounds the entire muscle?
Epimysium
187
Which connective tissue is inside each fascicle?
Endomysium
188
Which connective tissue surrounds the muscle fascicle?
Perimysium
189
Which fixatives are commonly used to fix tissues?
Glutaraldehyde and formaldehyde
190
Which histological stain is commonly used to detect the myelin sheath? Why?
Osmium tetroxide as the myelin sheath is predominately lipid which is soluble in most of the common staining techniques.
191
Which hormone stimulates osteoclasts to reabsorb bone matrix leading to calcium in the blood?
Parathyroid hormone
192
Which muscle cells retain their mitotic activity?
Smooth muscle
193
Which nervous system contains myelinated neurones only?
Somatic (voluntary) nervous system
194
Which nervous system nervous system contains myelinated (CNS) and unmyelinated (PNS) neurones?
Autonomic (involuntary) nervous system
195
Which six features could distinguish cardiac muscle from other types of muscle?
-Branching -Centrally placed nucleus (doesn't occur in skeletal) -Intercalated discs -Adherens type junctions -Striations (don't occur in smooth) -Purkinje fibres
196
Which two histological forms of muscle are striated?
-Cardiac -Skeletal
197
Which type of cartilage has no perichondrium?
Fibrocartilage
198
Which type of muscle has the T tubules in line with A-I band junction?
Skeletal muscle
199
Which type of muscle has the T tubules in line with Z lines?
Cardiac muscle
200
Which type of secretion has vesicles in cell but not when released?
Merocrine (exocytosis)
201
Which type of secretion has vesicles pinched off from the cell membrance?
Apocrine
202
Which type of secretion involves the entire cell being released and disintegrating?
Holocrine
203
Why are shrinkage artefacts commonly created?
The dehydration and rehydration in slide preparation
204
Why do tissues need to be fixed?
-Macro molecules are cross linked, preserving cellular structure -Prevents autolysis -Prevents putrefaction
205
Why is histology important?
-Provides gold standard of diagnosis -Inform what specific type of treatment to give a patient
206
Why is the parasympathetic nervous described as having a cranio-sacral outflow?
Its cells begin in the cranial and sacral regions of the spinal cord
207
Why is the sympathetic nervous described as having a thoraco-lumbar outflow?
Its cells begin in the thoracic and lumbar regions of the spinal cord
