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Anatomical Basis Of Clinical Practice > Microanatomy > Flashcards

Microanatomy Flashcards

1
Q

Definition of a tissue

A

Collection of cells specialised to perform a particular function

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2
Q

What are the four types of tissue and what are their general functions

A

Epithelium - lining and covering
Connective tissue - support and protection
Nerve - fast communication
Muscle - movement

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3
Q

What is an organ

A

Part of the body that is more than one tissue that forms a structural unit responsible for a particular function

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4
Q

Describe the structure of the cell membrane

A

Phospholipid bilayer
Contains embedded membrane proteins but also peripheral membrane proteins
Fluid mosaic model

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5
Q

Label the diagram of cell membrane

A

See lecture “cells 1”

Slide 11

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6
Q

What is the function of cholesterol in the cell membrane

A

Maintains fluidity in all temperatures

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7
Q

What is a glycoprotein

A

Protein with carbohydrate attatched

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8
Q

What is a glycolipid

A

Lipid with carbohydrate attatched

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9
Q

What are the functions of the cell membrane

A
  • structural support
  • compartmentalisation - special activities are contained and independently regulated
  • selectively permeable membrane - regulates passage of specific solutes
  • signal transduction - responds to and transmits stimuli
  • intercellular interaction - allows cells to recognise and signal each other - cell adherence - regulates entry and exit of molecules
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10
Q

What does compartmentalisation mean in terms of the cell membrane

A

Specialised activities are contained and independently regulated

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11
Q

What does signal transduction mean in terms of a cell membrane

A

Responds to and transmits stimuli

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12
Q

What does intercellular interaction mean in terms of cell membrane

A

Allows cells to recognise and signal each other
Cell adherence
Regulates entry and exit of molecules

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13
Q

Is surface if the membrane hydrophilic or hydrophobic. Why?

A

Hydrophilic because the surfaces are formed by the polar head groups of the lipid molecules

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14
Q

Is the inner portion of the cell membrane hydrophilic or hydrophobic? Why?

A

Hydrophobic because the fatty acids of the lipid molecules face each other

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15
Q

What are three types of lipids found in the cell membrane

A

Phospholipids, cholesterol and sphingolipid (nervous tissue)

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16
Q

What are the four types of proteins found in cell membranes

A

Transporters
Anchors
Receptors
Enzymes

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17
Q

What is the role of transporters in the cell membrane

A

Allow passage of small ions, molecules and water in either direction
Gap junction

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18
Q

What is the role of anchors in the cell membrane

A

Anchor the intercellular cytoskeleton to the extracellular matrix (ECM)

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19
Q

What are is function of receptors in the cell membrane

A

Allow recognition and localised binding of molecules

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20
Q

What is the main role of the nucleus

A

To duplicate genetic information

Transcribes information necessary for synthetic processes

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21
Q

What is chromatin

A

Highly folded nucleoprotein complex that consists of DNA and structural proteins histones

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22
Q

What does a) heterochromatin indicate and what does b) euchromatin indicate

A

a) indicates cell is metabolically inactive

b) indicates active chromatin

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23
Q

How does heterochromatin and euchromatin appear in an electron microscope

A

Heterochromatin appears as dense staining and highly condensed
Euchromatin appears as lightly-staining/ electron-lucid

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24
Q

What happens in the nucleolus

A

Site of ribosomal RNA synthesis and initial ribosomal assembly

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25
Q

Describe the nuclear envelope

A

Double membrane with a perinuclear space
Continuous with rER
Inner membrane supported by nuclear lamina
Pores

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26
Q

Label the diagram of the nuclear envelope

A

See lecture 1 slide 19

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27
Q

Describe the nuclear pore complex (NPC)

A

Formed by the merging of inner and outer membranes

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28
Q

What is the role of nuclear pores

A

Mediate the active transport if proteins, ribonucleoproteins and RNAs between nucleus and cytoplasm

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29
Q

What has an impact on how many nuclear pores there are

A

More active the nucleus is in transcription then the greater number of pores

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30
Q

What is the function of the nuclear lamina

A

Supports nuclear envelope
Essential in DNA replication, transcription and gene regulation
Anchors heterochromatin
Important in spatial organisation of nuclear pore

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31
Q

What is the enzyme that generates ATP in the matrix of the mitochondria

A

ATP synthase

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32
Q

What is the purpose of Cristae in the mitochondria

A

Increase surface area

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33
Q

Label the mitochondria diagram see lecture 1 slide 22

A

Labelled

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34
Q

What other tasks are mitochondria involved in other than production of ATP

A

Cell signalling
Cellular differentiation
Cell death (apoptosis)
Maintains control of the cell and cell growth

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35
Q

Describe the structure of ER

A

Membrane continuous with nuclear envelope

Consists of flattened sacs (cisternae) and tubules with a fluid-filled lumen

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36
Q

What is the difference between Rough ER and smooth ER

A

Rough has ribosomes located in membrane + more flattened in appearance
Smooth has none + more tubular in appearance

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37
Q

What is the function of smooth ER

A

Synthesises lipids
In striated muscle it is used as a calcium store
Enzymes within SER can help eliminate toxins, drugs, alcohol - prominent in hepatocytes (liver drugs to break down alcohol)
Carbohydrate metabolism - break down glucose to glycogen

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38
Q

What is the function of rough ER

A

Synthesis of secretory proteins and membrane proteins
Polypeptides assembled on the bound ribosomes and threaded into the ER lumen
Addition of carbohydrates to proteins
Folding of polypeptide chain - occurs in ER lumen
Quality control

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39
Q

What is the describe and state the function of free and fixed ribosomes

A

Free: scattered throughout the cytoplasm; assemble proteins for internal use
Fixed: fixed to RER; assemble proteins for export

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40
Q

Describe the structure of Golgi apparatus

A

A stack of flattened membranous sacs called cisternae

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41
Q

Functions of the Golgi apparatus

A

Modify products of the ER - glycosylation
Storage
Sorting and packaging of molecules into vesicles for transport
Shipping of secretory vesicles

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42
Q

In which direction through the Golgi apparatus does membrane modification occur

A

Cis to trans

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43
Q

In the Golgi apparatus which is the receiving face and which is the shipping face

A 
Cis = receiving
Trans = shipping
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44
Q

Describe lysosomes

A

Membranous sacs/vesicles containing hydrolytic enzymes

Involved in autophagy and heterophagy

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45
Q

What does autophagy mean

A

Destroy and recycle organelles and macromolecules from within the cell

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46
Q

What is heterophagy

A

Destroy material and extracellular matter that has been phagocytosed/ endocytosed by the cell

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47
Q

What is the difference between primary and secondary lysosomes

A

Primary: those which have yet to begin a digestive event - fuse with a phagosome
Secondary: where digestion proceeds

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48
Q

What is the name of the membrane bound vesicle that contains undigested material after lysosome action

A

Residual body

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49
Q

What are the seven steps of heterophagy

A
  1. Chemotaxis and adherence of microbe to phagocyte
  2. Ingestion of microbe by phagocyte
  3. Formation of phagosome
  4. Fusion of phagosome with a lysosome to form a phagolysosome
  5. Digestion of ingested microbe by enzymes
  6. Formation of residual body containing indigestible material
  7. Discharge of waste materials
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50
Q

Describe autophagy

A
  1. Phagophore formed - encloses cellular cargo?
  2. Autophagosome formed
  3. Fusion with lysosome
  4. Autophagolysome formation and cellular cargo degradation
  5. Products of degradation released back into cytoplasm
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51
Q

What is the function of the cytoskeleton

A
  • gives cell shape and mechanical resistance to deformation
  • actively contract - allows cell to migrate/move
  • involved in cell signalling pathways
  • involved in uptake of extracellular material (endocytosis)
  • segregates chromosomes during cellular division
  • involved in intracellular transport (move through cell)
  • forms specialised structures such as flagella and cilia
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52
Q

What are the 3 types of filament within the cytoskeleton of a cell and what are their functions

A

Microfilaments (actin): determine shape of cell’s surface & control locomotion
Microtubules: determine positions of membrane enclosed organelles and direct intracellular transport
Intermediate filaments: provide mechanical strength - resist tension - cell to cell adherence

See “cells 3” lecture, slide 4 for diagrams

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53
Q

How are intermediate filaments involved in cell adherence

A

Transmit shearing forces through desmosomes between cells

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54
Q

Why can staining for intermediate filaments be useful

A

If a cell in an organ becomes cancerous and spreads - will carry intermediate filament - so you can identify where the cancer originated (different intermediate filament subtypes for different types of cells)

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55
Q

What do epithelial cells attach to basal lamina through

A

Hemidesmosomes

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56
Q

Describe the structure of microfilaments

A

Actin filaments are connected deep to the plasma membrane

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57
Q

Describe the role of microfilaments

A

Essential for cell movement and cell shape - associate with myosin to form contractile structures (contract and relax)
Role in phagocytosis - move to engulf
Shape the cell membrane forming lamellipodia and filopodia
Form core of microvilli

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58
Q

Describe the structure of microtubules

A
  • Hollow tubes formed from molecules of alpha and beta subunits
  • 13 subunits form protofilaments that are arranged as a helix - gives it polarity
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59
Q

What is the role of microtubules

A
  • Form tracks that determine the location and movement of organelles and intracellular vesicles
  • grow from an area (centrosome) and extend to the cell periphery
  • form mitosis spindle used in cell division
  • form the core of cilia and sperm cells
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60
Q

Describe the structure of centrioles

A
  • important part of centrosomes (main place where microtubules are organised)
  • arranged in pairs within the centrosome
  • can be the basal body - the anchorage point of microtubules and other proteins
61
Q

Describe the structure of cilia

A
  • hair like cellular appendages with microtubules at the centre
  • arranged as a ring of 9 special doublet microtubules with a single pair of microtubules at the centre (9+2 arrangement)
  • anchored into a basal body
  • 10-15 um long
    For diagram see lecture “cells 3” slide 14
62
Q

What is the function of cilia

A

In humans: move fluid over surface of cell in one direction

63
Q

Where can cilia be found

A

Respiratory tract and female reproductive tract

64
Q

Describe the structure of flagella

A
  • hair like cellular appendages that have a bundle of microtubules at the centre
  • longer than cilia (up to 200um long)
  • 9 doublet microtubules and 2 single central microtubules
65
Q

What is the function of flagella

A

Locomotion:

Contain motor protein dynein- helps movement - whip like motion due to length

66
Q

Where can flagella be found

A

Sperm cells

67
Q

Describe the structure of microvilli

A
  • finger-like protrusions on the apical surface of epithelium
  • number and shape correlate to absorptive capacity
  • formed from actin microfilaments typically 1-3um long
  • actin anchors to the terminal web which stiffens the microvilli keeping the actin bunches at right angles to the cell
  • terminal web is composed of intermediate filaments
68
Q

8 functions of skin

A 
Protection - barrier
Control of evaporation
Sensation - nerve endings
Absorption - eg nicotine patch
Manufacture vitamin D - from UV - needed for calcium absorption
Thermoregulation
Storage and synthesis - storage of lipids and water
Excretion - perspiration
69
Q

Draw and label the strata of epidermis

A

Skin lecture

Slide 7

70
Q

What is the function of keratinocytes, melanocytes, Langerhans cells and merkel cells

A

Keratinocytes- produce keratin
Melanocytes - synthesise pigment melanin - located in basal layer
Langerhans cells - antigen presenting - form part of immune system - found in spinous layer
Merkel cells - sensitive mechanoreceptors - essential for light touch

71
Q

What can a change in size or appearance of moles sometimes indicate

A

Dysplasia which can progress to malignant melanoma

72
Q

Draw a labelled diagram of the layers of skin including the sub layers of the dermis

A

See skin lecture

73
Q

What is the dermis composed of

A

Dense regular connective tissue - abundant in collagen

74
Q

Give the name for the smooth muscle bundle associated with hair follicles

A

Arrector pili muscle

75
Q

What are the three types of unencapsulated receptors in the skin

A

Merkel cells:
- light touch and sensing an objects texture

Free nerve endings:
- temperature, pain, itching

Root hair plexuses:
- detects movement of hairs

76
Q

Name the four encapsulated receptors in skin

A

Meissen (tactile) corpuscles:
- light touch

Pacinian (lamellar) corpuscles:
- sensing coarse touch, pressure and vibrations

Krause end bulbs:
- genitalia - sense low frequency vibrations

Ruffin corpuscles:
- stretch or twisting

77
Q

What are the structural elements of CT

A

Cells
Fibres
Ground substance

78
Q

Name and describe the main cell in CT

A

Fibroblast

V active
Produces fibres and ground substance
Abundant and irregularly branched cytoplasm 
Extensive RER
well developed golgi
When inactive - fibrocytes
79
Q

What are the three types of fibres in CT

A

Collagen
Elastic
Reticular

80
Q

Describe type I to IV of collagen

A
  1. Tensile strength - 90 % of total collagen
  2. In hyaline and elastic cartilage
  3. Reticulum - wound healing - lymphoid organs
  4. In basal lamina
81
Q

How is a collagen fibre assembled

A
  1. 3 @polypeptide chains combine - procollagen
  2. Procollagen secreted from cell - proteolytic enzymes cleave loose ends - forms tropocollagen
  3. align linear to form collagen fibril
  4. Fibrils assemble to form collagen fibre
82
Q

Describe glycosaminoglycans

A

Unbranched polysaccharide chains composed of repeating disaccharide units
Very large and attract water
Maintain tissue architecture - high viscosity
Provide passageway between cells - allows cell migration

83
Q

Describe the three types of ordinary ct

A

Loose areolar:

  • pliable and mesh like
  • hold structures in place

Dense irregular:

  • resistance and protection
  • lots of collagen fibres - irregular arrangement
  • found in dermis, submucosa of digestive tract, periosteum, fibrous capsules of organs

Dense regular:

  • resistance in one direction/plane
  • collagen aligned fo resist stress - run parallel
  • tensile strength
  • found in: ligaments, tendons and aponeuroses
84
Q

Describe adipose tissue

A

Fat cells (adipocytes)
Lipid droplet surrounded by thin layer of cytoplasms and nucleus
Function:
- energy store, insulation, cushions
Found:
- under skin, kidneys, within abdomen, breasts

85
Q

briefly describe collagen fibres

A 
Tough 
• Provides high tensile strength • Stretch
resistant
• Most abundant
protein – 25%
of total protein
mass
86
Q

briefly describe elastic fibres

where are they mainly found

A 
• Long, thin
fibres
• Allow for stretch and
recoil
- Found in dermis, elastic arteries (aorta), lung, certain
cartilages
87
Q

briefly describe reticular fibres

A
  • Branched, thin
    collagenous fibres
  • form extensive delicate networks
  • need specialised stains in order to see
  • made up of type 3 collagen
  • individual fibres - do not form bundles
88
Q

what is the cause of scurvy

A
  • lack of vitamin C
  • Vitamin C is essential for collagen synthesis
  • Imperfect collagen production causing abnormal bone growth, fragile capillaries leading to bleeding (gums) and loss of teeth etc
89
Q

what is the cause of Ehler-Danos Syndrome

A
  • Caused by a defect in the structure, production, or processing of collagen or proteins that interact with collagen
  • Characterised by skin extensibility, joint hypermobility and tissue fragility
90
Q

what is the cause of Marfan syndrome and symptoms

A
  • defect in FBN1 gene which encodes fibrillar-1 i.e lack of fibrrillin in elastic fibres
  • tall, thin individuals with long limbs, large hands, sunken chest
  • defects of the heart valves and aorta - prone to aortic rupture
  • typically have flexible joints and scoliosis
91
Q

briefly describe ground substance and state its function

A
  • highly hydrated gel, interstitial (tissue) fluid
  • resists compressive forces on the matrix - provides mechanical strength
  • functions as a molecular sieve through which nutrients, metabolites and hormones diffuse between blood capillaries and cells
  • composed of glycosaminoglycans (GAGs), proteoglycans and adhesive glycoproteins
92
Q

what are primary tissues and organs in relation to the lymphoreticular system. give two examples

A
  • where lymphocytes are formed and/or mature
  • Bone marrow
  • thymus
93
Q

what are secondary tissues and organs in relation to the lymphoreticular system. give two examples

A
  • peripheral structures that maintain mature but naive lymphocytes and initiate immune response

eg:

  • lymph nodes
  • spleen
  • Mucosa-associated lymphoid tissue (MALT)
  • Gut-associated lymphoid tissue (GALT)
94
Q

what is the function of B-lymphocytes

A
  • Involved in humoral immunity
  • Produce antibodies (proteins that recognise foreign substances (antigen) and attach themselves to it
  • Mark invaders for destruction by other immune cells
95
Q

what is the function of T-lymphocytes

A
  • Involved in cell-mediated immunity (activation of phagocytes, antigen-specific cytotoxic T lymphocytes and the release of cytokines in response to an antigen; targets transformed and virus-infected cells for destruction by specific ‘killer’ cells
  • do not produce antibodies
96
Q

what are the four types of supporting cells of the lymphoreticular system

A

reticular cells
epithelioreticular cells
dendritic cells
macrophages

97
Q

what is the function of reticular cells in supporting the lymphoreticular system

A
  • Secrete type III collagen (reticular fibres) and ground substance
  • Form intricate network in which the immune cells reside
98
Q

what is the function of epithelioreticular cells in supporting the lymphoreticular system

A
  • Specific to the thymus

- Assist with T lymphocyte education

99
Q

what is the function of dendritic cells in supporting the lymphoreticular system

A
  • Antigen-presenting cells (APCs)

- Monitor local environment for antigen which they process and present to lymphocytes

100
Q

what is the function of macrophages in supporting the lymphoreticular system

A

Work both as APCs and phagocytes

101
Q

describe the appearance of a lymphoid follicle

A
  • Spherical accumulation of lymphocytes
  • Pale staining germinal centre (activated B immunoblasts)
  • Dark stained outer corona/mantle – represents a ring of small transient B lymphocytes
102
Q

describe the appearance and function of the thymus

A
  • Primary lymphoid organ responsible for programming
  • CT capsule & septa divide organ into lobules
  • Contains T lymphocytes (thymocytes) in a meshwork of epithelioreticular cells
  • It has no lymphoid follicles
103
Q

histologically how can you tell the difference between the cortex and medulla of the thymus

A 
cortex = dark staining 
medulla = light staining (less cells)
104
Q

what is contained in the cortex of the thymus

A
  • naive T lymphocytes that migrate to medulla

- Macrophages responsible for phagocytosis of T lymphocytes that do not fulfil thymic education requirement

105
Q

what is contained in the medulla of the thymus

A
  • maturing t lymphocytes (assessment of immunocompetence)
  • Hassall’s corpuscles
  • immunocompetent T lymphocytes pass Fromm medulla into blood circulation
106
Q

what cell makes up Hassall’s corpuscle of the medulla and what do they produce

A

Concentrically arranged, flattened epithelioreticular cells producing keratohyalin (similar to SSK epithelium)

107
Q

what is the blood-thymus barrier composed of and what is its function

A
  • Prevents circulating antigen reaching the T lymphocytes before their immunocompetence has been determined

Comprised of:

  • Continuous endothelium of blood capillaries
  • Thick basal lamina
  • Epithelioreticular cells
  • Macrophages
108
Q

describe the histological appearance of lymph nodes and their function

A
  • Deal with lymph-borne antigens - all tissue fluid-derived lymph is filtered by at least one node before returning to the circulation
  • Outer curved boundary – afferent lymphatic vessels enter
  • Hilum (H) – efferent lymphatics leave (also vascular & neural connections)
109
Q

describe the outer cortex, inner cortex (paracortex) and medulla of a lymph node

A

Outer cortex:

  • Subcapsular sinus & trabecular sinuses
  • Meshwork of reticular fibres, dendritic cells & macrophages
  • B lymphocytes organised into follicles

Inner cortex (paracortex):

  • Few or no follicles
  • mostly T lymphocytes

Medulla:

  • medullary cords- branched extensions of lymphoid tissue from inner cortex
  • separated by medullary sinuses
  • dendritic cells and macrophages occur
110
Q

what is the name of the connective tissue that surrounds the entire muscle

A

epimysium

111
Q

what is the name of the connective tissue that surrounds each fascicle of a muscle

A

perimysium

112
Q

what is the name of the connective tissue that surrounds each fibre of a muscle

A

endomysium

113
Q

what gives muscle its striated appearance

A

Striations represent the repetitive contractile units, sarcomeres, consisting of segments of myofilaments

114
Q

what is the name for the distance between 2 z-lines in a muscle fibre

A

Sarcomere

115
Q

what are the light bands and dark bands in muscle fibres

A 
I band (Light):
- Composed of actin myofilaments that are anchored to the z-line

A band (Dark):

  • Represents the overlap between actin and myosin except at the H band
  • Myosin anchored to m-line
116
Q

what is the function of t tubules in muscle fibres

A

Function of t-tubules is to carry wave of depolarisation into fibre for contraction to occur

117
Q

what is the function of blood

A
  • Delivery of nutrients and oxygen directly or indirectly to cells
  • Transport of wastes and carbon dioxide away from cells
  • Delivery of hormones and other regulatory substances to and from cells and tissues
  • Maintenance of homeostasis by:
    acting as a buffer
    participating in coagulation
    assisting with thermoregulation
  • Transport of humoral agents and cells of the immune system that protect the body from pathogenic agents, foreign proteins, and transformed cells e.g. cancer cells
118
Q

what is the lifespan of a red blood cell

A

120 days

119
Q

Why are erythrocytes biconcave?

A

↑ Surface area – more haemoglobin molecules closer to plasma membrane

Less distance for O2 and CO2 to diffuse

Extremely deformable

Less likely to rupture

120
Q

what is the lifespan of a leukocyte

A

Life span of up to several years

121
Q

what is the difference between granulocytes and agranulocytes

A

Granulocyte:

  • Cytoplasm packed with granules
  • Nucleus has 2 or more lobes (polymorphonuclear)
  • Neutrophils, Eosinophils & Basophils

Agranulocyte:

  • Cytoplasm with few or no granules
  • Nucleus not lobed
  • Mononuclear
  • Lymphocytes & Monocytes
122
Q

describe a neutrophil:

  • percentage of all WBCs
  • physical appearance
  • when it responds
  • life span
A
  • 60-70%
  • Nucleus has 2-5 lobes
  • Numerous cytoplasmic granules
  • Respond most quickly to tissue destruction by bacteria or fungus
  • Numbers increase during acute bacterial infections such as meningitis and appendicitis
  • Short life span (1-2 days)
123
Q

describe a eosinophil:

  • percentage of all WBCs
  • physical appearance
  • when it responds
A
  • 2-4% of circulating WBCs
  • Bilobed nucleus
  • Large refractile granules (lysosomes)
  • Regulate local inflammatory responses due to allergic or parasitic action
124
Q

describe a basophil:

  • percentage of all WBCs
  • physical appearance
  • when it responds
A

Less than 1% of circulating WBCs
Irregularly-lobed nucleus
Numerous large overlying granules which often obsucre the nucleus
Granules contain heparin (anti-coagulant) and histamine (vasodilator)
Associated with systemic inflammation and allergies

125
Q

describe a lymphocyte:

  • percentage of all WBCs
  • physical appearance
  • when it responds
A
  • 20-25% of circulating WBCs
  • Nucleus is spherical and densely stained; no granules
  • Usually present in tissues

Involved in adaptive immune responses:

  • B-lymphocytes → plasma cells (produce antibodies)
  • T-lymphocytes (cell-mediated response)
126
Q

describe a monocyte:

  • percentage of all WBCs
  • physical appearance
  • when it responds
A
  • 3 – 8 % of circulating WBCs
  • Kidney/U-shaped nucleus
  • Large cell (12- 20μm)
  • Transform into a macrophage in tissues and organs (e.g. osteoclasts, Kupffer cells, alveolar macrophages)
127
Q

what is the order of abundance for white blood cells

A 
Neutrophil
Lymphocyte
Monocyte
Eosinophil
Basophil

Never let monkeys eat bananas

128
Q

describe haemostasis

A

When endothelial injury occurs, the endothelial cells stop secretion of coagulation and aggregation inhibitors and instead secrete von Willebrand factor which initiates the maintenance of haemostasis after injury
Platelets and fibrin (in blood plasma) bind together with cells to form platelet plug

Three major steps involved:

  1. Vasoconstriction of blood vessel wall
  2. Temporary blockage of a break by a platelet plug - platelets attach to exposed collagen of vessel wall and release the contents of their granules, leading to aggregation of other platelets to the area
  3. Blood coagulation, or formation of a fibrin clot – a fibrin mesh (from blood plasma) binds together with cells and platelets
129
Q

List and describe the layers of the wall of the heart.

A

Epicardium:

  • Visceral pericardium - simple squamous epithelium
  • Subepicardium - loose connective tissue and adipose tissue containing coronary vessels and nerves that supply the heart

Myocardium:

  • Thickest layer
  • Bundles and layers of cardiac muscle cells

Endocardium:

  • Smooth inner lining of endothelial cells
  • Subendocardium - loose connective tissue containing small blood vessels and branches of the conducting system of the heart
130
Q

Describe the impulse conducting system of the heart.

A

Sinoatrial (SA) Node – Pacemaker:

  • Located in wall of superior vena cava & right atrium, deep to epicardium
  • Specialised cardiac muscle fibres (lots of CT between fibres)
  • Possesses its own blood supply
  • Causes atrial contraction

Atrioventricular (AV) Node:

  • Located in septum between atria
  • Begins ventricular contraction

Atrioventricular Bundle – Bundle of His:

  • Bundle of fibres that enter interventricular septum
  • Divides into 2 branches of Purkinje fibres

Purkinje fibres:

  • Occur in dense CT of endocardium
  • Specialised cardiac muscle fibres – larger (x2 approx.)
  • Supply papillary muscles first, then apex of heart
  • Causes wave of ventricular contraction
131
Q

Compare and contrast the structure of arteries and veins.

A

Arteries:
- Carry oxygenated blood (except pulmonary artery)
- Takes blood away from the heart
- Wall thick in comparison to lumen diameter
- No valves
- Two main types;
> Elastic arteries(conducting vessels)
> Muscular arteries (distributing vessels)
Also, arterioles

Veins:

  • Carry deoxygenated blood (except for pulmonary veins)
  • Takes blood to the heart
  • Walls are thin in comparison to lumen diameter
  • Tunica media relatively thin compared to arteries
  • Tunica adventitia relatively larger compared to arteries
  • Possess valves
132
Q

describe the layers of a vessel wall

A

see heart and blood vessels lecture - slide 15 for diagram

Tunica Intima (Interna):
- Endothelium & CT (subendothelium)

Tunica Media:
- Smooth muscle, collagen and elastic fibres (relative amounts)

Tunica Adventitia (Externa):

  • Loose connective tissue (relative amounts)
  • Can have blood vessels and nerves
133
Q

describe the three types of capillaries

A

Continuous capillaries:arecontinuousin the sense that the endothelial red blood cells provide an uninterrupted lining, and they only allow smaller molecules, such as water and ions to pass through their intercellular clefts

Fenstrated: These are found in some tissues where there is extensive molecular exchange with the blood such as the small intestine, endocrine glands and the kidney. The ‘fenestrations’ are pores that will allow larger molecules though. Thesecapillariesare more permeable than continuouscapillaries.

Discontinuous capillaries:have open spaces between endothelial cells are very permeable and sometime permit the passage of blood cells between them. These are found in the liver, spleen and bone marrow.

134
Q

name 6 functions of the respiratory system

A
  • Moves air to and from exchange surfaces
  • Exchange of CO2 and O2 between atmosphere and blood
  • Protects:
    >airways from environment e.g. dehydration, temperature changes, foreign bodies;
    > airways & other tissues from pathogens;
  • Sensation of smell
  • Sound production
  • Assists in regulation of blood volume, blood pressure, & control of body fluid pH
135
Q

describe the function of nasal conchae

A
  • Increase surface area of nasal cavity
  • Lined with PSCC epithelium
  • Contain venous sinuses and tubuloacinar seromucous glands
  • Cause air turbulence to trap foreign matter
  • Blood acts as a heat exchanger, warming the incoming air
  • Filters air- pollutants are trapped in the mucus
136
Q

function of the trachea

A

Conducts air into thorax
Withstands stretch
Transports mucous blanket – mucociliary escalator

137
Q

what is the function of the larynx

A

Connects pharynx to trachea

Responsible for phonation (phonetics - speech sounds)

Epiglottis guards against entry of foreign bodies

138
Q

describe - physical features and function - of the pleura of he lungs

A
  • Two layers of opposing mesothelium
    >Visceral pleura
    >Parietal pleura
  • Composed of a fibroelastic CT
  • Pleural cavity in-between containing serous fluid
  • Protection from friction against chest wall during breathing
139
Q

Name the types of epithelium found in different parts of the alimentary tract.

A

Stratified Squamous Non-keratinising:

  • oral cavity
  • oesophagus

Simple Columnar:

  • stomach
  • small intestine - duodenum, jejunum, ileum
  • large intestine/colon
  • Simple columnar→ SSNK → SSK:
  • rectum
  • anus
140
Q

Describe the epithelial specialisations of the oral cavity and oesophagus.

A

Hard palate:

  • Anterior 2/3
  • Lined with SSK epithelium
  • Underlying bone

Tongue:

  • Dorsum – specialised epithelium (taste buds and papillae)
  • Ventrum – SSNK epithelium

Gums (Gingiva):
- SSK epithelium

Soft palate:

  • Movable posterior 1/3 of palate
  • Lined with SSNK epithelium but no bony skeleton

Cheeks:
- SSNK epithelium

141
Q

Describe the epithelial specializations of the small and large intestines and their principal epithelial cells.

A

Small intestine:
- Large surface area required to maximise absorption - entire small intestine has SA of 250m2
- Three features facilitate this:
1. Pilcae Circulares:
> circular ridges projecting into the gut lumen
2. Villi:
> finger-like structures projecting from plicate circulares
> crypts of Lieberkühn at base of villi
3. Microvilli:
> microscopic finger-like structures projecting from apical surface of absorptive enterocytes

Large Intestine:
- Simple tubular glands containing numerous goblet cells (mucus production), colonocytes (absorptive) and enteroendocrine cells

142
Q

Describe the relationship between the exocrine and endocrine components of pancreas and the structural features of each

A

Organ divided into lobules by CT septa (lobulated)

Exocrine:

  • Serous acini and branched ducts
  • Produce enzymes for digestion of food, including trypsinogen, lipase and amylase.
  • Produced in an inactive form to avoid self-digestion

Endocrine:

  • Islets of Langerhans & blood capillaries
  • Islet cells produce hormones including insulin, glucagon, somatostatin and pancreatic polypeptide
143
Q

list some of the functions of saliva

A
  • Digestive, lubricating and protective functions
  • Limits bacterial activity
  • Epidermal growth factor released to aid wound healing
  • Gustin released to help detect taste
  • maintains integrity of tooth enamel
144
Q

list some of the functions of the liver

A
  • Exocrine gland function – production of bile
  • Endocrine gland function – production of plasma proteins
  • Nutrients absorbed in digestive tract processed and stored in liver for use by other parts of the body e.g. carbohydrates stored as glycogen
  • Degrades toxins, drugs, alcohol etc.
  • Destruction of worn out red blood cells
145
Q

what is the function of Juxtaglomerular Apparatusin the kidneys

A

Function: to monitor and adjust blood pressure

146
Q

what type of epithelium lines the PCT

A

simple cuboidal

147
Q

describe the epithelium lining of the loop of Henle

A

Thin portion lined by simple squamous epithelium

Thick portion lined by simple cuboidal epithelium

148
Q

describe the epithelium lining of the collecting ducts in the kidney

A

Lined by simple cuboidal/columnar epithelium

149
Q

describe the development of endocrine glands

A

see endocrine lecture slide 4 for diagram

Multicellular glands begin as down-growing buds of cells as in B3 & B4

Endocrine glands develop by the isolation of the bud of cells from the surface epithelium (C4)

This isolated mass then acquires its own blood supply (D4)

Anatomical Basis Of Clinical Practice (4 decks)

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