Endocrinology Anatomy Flashcards

1
Q

What is the anatomical position of the adrenal glands?

A

Superiomedially between the superior pole of the kidney and the crus of the diaphragm

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2
Q

What is the embryological origin of the cortex?

A

Mesoderm (similar to the gonads)

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3
Q

What is the embryological origin of the medulla?

A

Ectoderm (similar to the SNS)

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4
Q

What does the adrenal cortex secrete?

A

Steroid hormones
Mineralocorticoids (aldosterone)- electrolyte and fluid homeostasis
Glucocorticoids (cortisol) - CHO, protein, and lipid metabolism
Sex hormones - testosterone and oestrogen

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5
Q

What does the adrenal medulla secrete?

A

Catecholamines: (nor)adrenaline

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6
Q

What regulates glucocorticoid secretion?

A

Anterior pituitary adrenocorticotropic hormone (ACTH)

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7
Q

What regulates mineralocorticoid secretion?

A

RAAS and [K]plasma

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8
Q

What regulates secretion of medullary catecholamines?

A

SNS
Chromaffin cells
Thorcacic splanchnic nerves
Coeliac Plexus

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9
Q

What the the two layers of the adrenal gland?

A

Outer cortex

Inner Medulla

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10
Q

What invests the adrenal gland?

A

Dense fibrous capsule

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11
Q

What are the 3 layers of the adrenal cortex and what are their functions?

A

Remember GFR

  1. Zona Glomerulosa: large amounts of sER and mito; secretes mineralcorticoid hormones (aldosterone) controlled by RAAS and [K]plasma, RAAS is regulated by the macula densa
  2. Zona Fasciculate: middle and broadest; cytoplasm rich in sER, mito, and lipids; secretes glucocorticoids (cortisol); Also secretes sex hormones

Zona Reticularis: inner most; fewer lipid droplets; secretes small quantities of androgens and glucocorticoids

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12
Q

How is aldosterone release triggered?

A
  1. Decreased arterial pressure
  2. Decreased GFR
  3. Decreased macula densa NaCl
  4. Increased renin production
  5. RAAS pathway
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13
Q

Where, in the kidney, does aldosterone act on?

A

Renal tubules
Increases Na+ and H2O retention
In turn increasing ECF volume and arterial BP

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14
Q

Can aldosterone secretion be triggered by ACTH?

A

No

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15
Q

What controls cortisol secretion?

A

Hypothalamus (CRH) –> Anterior Pituitary (ACTH) –> Adrenal Cortex (Cortisol)

Hypothalamus stimulus: stress, time of day, illness

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16
Q

What is the medulla composed of?

A

Closely packed clusters of secretory cells

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17
Q

What does the medulla secrete?

A

Catecholamines: (nor)adrenaline

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18
Q

What forms the endocrine pancreas?

A

Islets of Langerhans

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19
Q

Where are the islet of Langerhans found?

A

Scattered throughout the exocrine glandular tissue
Vary in size
MOST NUMEROUS in tail of pancreas

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20
Q

What cells comprise the endocrine pancreas?

A

B-cells (70%) - secrete insulin in response to hyperglycaemia –> Promotes glucose uptake by GLUT4

A-cells (25%) - secretes glucagon –> respond to hypoglycaemia

D-cells (4%) - secrete somatostatin –> GI Function + inhibit alpha and beta-secretion

PP-cells (1%) - secrete polypeptide hormone

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21
Q

What kind of hormone is insulin?

A

Peptide

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22
Q

Where is insulin synthesised?

Describe the pathway

A
  • b-cells of pancreas
  • at eER as preproinsulin
  • preproinsulin is cleaved to form proinsulin
  • proinsulin is then cleaved at the Golgi to form insulin
  • insulin is then packages in vesicles and remains in the cytoplasm for secretion
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23
Q

Where does the pancreas lie?

A

Retroperitoneal
Transversely across the posterior abdominal wall
Posterior to the stomach
Between the duodenum on the right and the spleen on the left

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24
Q

What lies on the anterior margin of the pancreas?

A

Root of the transverse mesocolon

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25
Q

Where does the exocrine secretions of the pancreas come from?

A

Pancreatic juice from acinar cells, which enters the duodenum

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26
Q

Where is the pancreas positioned relative to the duodenum

A

Head of pancreas is embraced by the C-shaped curve of duodenum

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27
Q

How is the uncinate process of the pancreas positioned?

A

Inferior to the head of the pancreas, extends medially to the left, posterior to the SMA/V

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28
Q

What structure do the pancreatic and common bile ducts form? and where?

A

Hepatopancreatic amuplla (of Vatar), which opens into the descending duodenum at the greater dudenal papilla (8-10cm from pylorus)

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29
Q

What structure controls secretions of the pancreas and gall bladder?

A

Sphincter of Oddi

CCK cause it to relax (and cause gallballder to contract)

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30
Q

Where do the pancreatic arteries branch of?

A

Splenic artery

Main: Greater pancreatic artery

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31
Q

What is the pancreatic venous drainage?

A

Pancreatic veins are tributaries of the splenic and SM parts of the hepatic portal vein
Most empty into the splenic vein

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32
Q

What is the functional unit of the exocrine pancreas

A

Pancreatic acini

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33
Q

What type of epithelium lines the exocrine pancreatic ducts?

A

Simple cuboidal

Larger ducts: stratified cuboidal

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34
Q

What do the cells in the pancreatic duct secrete?

A

Water and HCO3-

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35
Q

How many layers of fascia and fat are they kidneys surrounded by? And name them.

A

Perinephric fat (capsule) - surround the kidneys and adrenal glands and is continuous with the renal sinus, enclosed by a membranous layer

External to the fascia is the paranephric fat

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36
Q

Where are the adrenal glands located?

A

Between the superiomedial aspects of the kidneys and the diaphragmatic crura, where they are surrounded by connective tissue containing perinephric fat

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37
Q

Of what type of tissue is the capsule of the adrenal glands formed?

A

Fibrous connective tissue

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38
Q

What tissue lies outside the capsule?

A

Loose connective tissue containing white fat (unilocular adipose tissue)
It’s called perinephric fat

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39
Q

The cells forming the zona fasciculate appear pale in H&E stained section and contained empty, small rounded profiles. What is an alternative name for these cells?

A

Spongiocytes

A spongiocyte is a cell in the zona fasciculata of the adrenal cortex containing lipid droplets that show pronounced vacuolization

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40
Q

What is the diameter of a RBC?

A

7-8micrometers

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41
Q

What receives blood first the medulla or the cortex?

A

The medulla receives blood first from the capillaries and the sinusoids of the adrenal cortex second from arterioles passing from the capsule to the medulla

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42
Q

Where does the pancreas lie?

A

Retroperitoneal in the “stomach bed”

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43
Q

What type of capillaries are in the Islets of Langerhans

A

Fenestrated

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44
Q

What is the GTT important for?

A

Diagnosing of disorders of CHO metabolism

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45
Q

What are the main target tissues for insulin?

A

Muscle and adipose tissue

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46
Q

Blood glucose will be elevated after ingestion of a fixed dose of glucose.
After how long would the [glucose]blood take to return to normal?

What about a diabetic person?

A

Within 2 hours

Diabetic: significantly longer

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47
Q

What enzyme is used in ExacTech Blood Glucose Monitoring systems?

A

Glucose oxidase

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48
Q

What happens to glucose as it is filtered by the kidney?

A

Reabsorbed by SGLT2 (90%) at the PCT and SGLT1 (10% at the descending loop of Henle at the apical lumen, and into the blood via GLUT2 at the basolateral surfaces.

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49
Q

What is the normal concentration of glucose in the urine?

A

0-0.8mmol/L

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50
Q

What is the glucose reabsorption threshold? And what happens if this is exceeded?

A

10.0mmol/L

Glucosurea

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51
Q

What hormones/neurotransmitters increase by the procedure of taking blood?

A

Stress hormones

GH, adrenaline(nor), and cortisol
ACh

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52
Q

Which tissues metabolise glucose and what do they form?

A

Liver: glycogen
Muscle: glycogen
Adipose: triglycerides

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53
Q

How would the metabolism of glucose change as your body glucose concentration returns to resting values?

A

Increase glycogen synthesis

Decreased blood glucose levels

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54
Q

What tissues are totally dependent on glucose as an energy source? And why?

A

Brain - due to blood-brain barrier
RBCs - don’t have mitochondria for oxidation and energy production from alternative substrates
Testes - blood testis barrier

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55
Q

What different types of glucose transporters are found in the body? Which are in the kidneys?

A

GLUTs 1-5
SGLTs 1-2

Kidney:
SGLT1/2 and GLUT2

56
Q

What effect would you expect if an average meal were accompanied by oral administration of an inhibitor of alpha-glucosidase activity?

A

Alpha-glucosidase is inhibited by acrabose
This drug is an inhibitor of this enzyme which normally digests complex sugars (starch) and delays intestinal absorption of glucose.
Side effects? gas.

57
Q

What drug inhibits alpha-glucosidase? and how.

A

Acrabose

58
Q

Why might a patient with diabetes have [glucose]>11mM after an overnight fast?

A

Decreased insulin

Gluconeogenesis increases blood glucose.

59
Q

Why do diabetic patients tend to have nocturnal polyuria?

A

Glucose in the urine exerts osmotic pressures in the filtrate resulting in polyuria.

  1. Plasma glucose high
  2. Glucose filtered in the kidneys
  3. Glucose in filtrate exceeds reabsorptive capacity (>10mmol/L)
  4. Glucose in the tubule creates osmotic gradient and draws water into the filtrate.
  5. Polyuria.
60
Q

Why do patients with T1DM lose weight while eating plenty?

A

No insulin is produced at all
Lack of glucose in the cells
Catabolism of FA/AA

61
Q

Where does the adenohypophysis develop from?

A

dorsal outgrowth from the wall of the embryonic pharynx

62
Q

Where does the neurohypophysis develop from?

A

Down growth from the diencephalon

63
Q

What surrounds the pituitary gland?

A

Fibro-elastic capsule

64
Q

Where does the the fibrous capsule of the pituitary gland develop from?

A

Innermost meneges layer
Dura
Primitive pia matter

65
Q

In the adenohypophysis there are two types of secretory cells. What are they? And what do they represent?

A

Chromophobes - pale; exhausted secretory cells

Chromophils - dark; actively secreting cells

66
Q

In H&E staining, what do basophils bind to and what colour are they?

A
Basic stains (haematoxylin)
Dark purple colour
67
Q

In H&E staining, what do acidophils bind to and what colour are they?

A

Eosin (acidic dye)

Red

68
Q

How many different endocrine cells are found within the adenohypophysis?

A

5

69
Q

List the endocrine cells found within the adenohypophysis and their %

A
  1. Somatotrophs - 50% - Secrete growth hormone
  2. Lactotrophs - 20% - Secrete prolactin
  3. Corticotrophs - 10-15% - Secrete: POMC
    - Adrenocoticotropic hormone (ACTH)
    - b-lipotropin hormone (b-LPH)
    - a-melanocyte stimulating protein (a-MSH)
    - b-endorphin
  4. Tyrotrophs - 5% - Secrete thyroid stimulating hormone (TSH)
  5. Gonadotrophs - 10% - Secrete FSH and LH
70
Q

What type of capillaries are found within the adenohypophysis?

A

Fenestrated Capillaries

71
Q

Where does the thyroid gland develop from?

A

Thyroid gland develops from an ENDODERMAL downgrowth (the ‘thyroglossal duct’) from the floor of the developing pharynx

Derived from the base of the tongue
Thryoglossal duct
Passing through the hyoid bone

72
Q

What marks the site of down growth of the thyroid gland?

A

Foramen caecum at the back of the tongue

73
Q

Describe the gross structure of the thyroid gland

A

Two lobes connected by a midline isthmus

74
Q

Histologically what does the thyroid gland consist of?

A

Follicles

75
Q

Where is the thyroid?

A

Anterior neck

Wrapper in front of larynx

76
Q

Whats the weight of the thyroid?

A

approx. 20g

77
Q

What type of cells are thyroid follicles?

A

Epithelial structures
Simple
- Inactive follicles: low cuboidal or squamous
- Active follicles: columnar

78
Q

What hormones are synthesised in the follicles?

A
  1. Thyroxine (T4)

2. Tri-iodothyronine (T3)

79
Q

How does the thyroid cells concentrate iodide?

A

Iodine pump

80
Q

What hormone regulates the activity of the thyroid gland and where is it produced?

A

Thyroid releasing hormone (TRH) by the hypothalamus

81
Q

Which cell organelle produces the protein part of thyroglobulin?

A

eER

82
Q

Which cell organelle adds the sugar component to thyroglobulin?

A

Golgi Apparatus

83
Q

In the thyroid, what is colloid?

A

Iodinated glycoprotein, rich in thryoglobin, is a storage form of thyroxine

84
Q

Thyroid

Which enzyme, synthesised by the follicle cell, enables iodide to be converted to iodine?

A

Thyroid peroxidase

85
Q

How is thyroglobulin taken up by thryoid cells?

A

Pseudopodial extensions of the cytoplasm enclose droplets of thyroglobulin and bring them into the cell when thyroxine and tri-iodothyronine are required

86
Q

Where is thyroglobulin stored in the thyroid?

A

Colloids

87
Q

What is Hasimoto’s disease? How is it caused?

A
  • Hashimoto’s thyroiditis is an autoimmune disease
  • The thyroid is underactive
  • Patient is described as having hypothyroidism
  • Condition results because of antibodies to thyroid peroxidase (antimicrosomal antibodies) are produced
  • Infiltration of plasma cells, lymphocytes, macrophages
  • Germinal centre formation
  • Oncocytic change in epithelium (Hurthle cells)
88
Q

Where would you find Hurthle cells? And what are they?

A

Hashimoto’s thyroiditis

Hurthle cells = oncocytic change in epithelium

89
Q

Define glycoprotein

A

Any of a class of proteins which have carbohydrate groups attached to the polypeptide chain.

90
Q

What are colloids?

A

Found within thyroid follicles
Storage form of thyroid hormones T3/T4
Contain several enzymes

91
Q

What is the major chemical component of colloid

A

Thyroglobulin, an iodinated glycoprotein containing about 120 tyrosine residues

92
Q

How many and what are the hormones released by follicular epithelium of the thyroid?

A

Follicular cells:

  1. Tri-iodothyronin (T3)
  2. Thyroxine (T4)
Parafollicular cells (C-Cells)
1. Calcitonin
93
Q

Where are T3/T4 derived from?

A

T3 and T4 are iodinated derivatives of tyrosine

94
Q

Which is functionally more important T3 or T4?

A

T3

95
Q

What do thyroid follicular cells mainly produce? T3 or T4?

A

T4

96
Q

What triggers the hypothalamus to produce TRH?

A

Low levels of thyroxine (T4) in circulating blood

97
Q

What is the main function of T3 and T4?

A

Regular cell and tissue basal metabolism

98
Q

Define basal metabolic rate

A

The rate at which the body uses energy while at rest to maintain vital functions such as breathing and keeping warm.

99
Q

What is a sign of hypocalcaemia?

A

Twitching of face and arm muscles

100
Q

What other biochemical change can result from hypocalcaemia? And what can this cause?

A

Hyperphosphataemia

Severe itching and weakening of the bones

101
Q

What do C-cells (parafollicular cells) in the thyroid release?

A

Calcitonin

102
Q

Summaries the function of calcitonin

A

Released in response to elevated blood calcium levels

Reduces calcium levels in the blood by:

  1. Inhibiting the activity of osteoclasts
  2. Promotes absorption of calcium by bone
  3. Decreases reabsorption of calcium in the kidneys
103
Q

What is the role of osteoclasts?

A

Bone resorption

They are large multinucleated cells

104
Q

What is the normal serum concentration of calcium?

A

2.25-2.5mmol/L

105
Q

What hormones regulate blood calcium? And how do they do it?

A

Calcitonin - respond to increased calcium

PTH - respond to decreased calcium

106
Q

Where is PTH secreted from?

A

Parathyroid gland

Chief cells

107
Q

Where is the parathyroid gland located?

A

Posterior to the thyroid gland or sometimes embedded within the thyroid gland

108
Q

What types of cells are found in the parathyroid glands?

A

2 types of secretory cells

  1. Chief cells - secrete PTH
    - basophilic
  2. Oxyphil cells
    - acidophilic

1 other cell

  1. Water-clear cell: just chief cells with pools of glycogen
109
Q

How may parathyroid glands are there? And what is their weight?

A

4

120mg - combined weight

110
Q

Does the parathryoid gland posses a connective tissue capsule?

A

Yes

Thin fibrous capsule

111
Q

Where doe the parathyroid glands come from emrbyologically?

A
  • upper pair: from 4th brachial cleft (phayngeal pouches) and descend with thyroid
  • lower pair: from3rd brachial cleft and descend with thymus
112
Q

Where does the external jugular vein run?

A

EJV runs vertically across the sternocleidomastoid muscle towards the neck of the mandible

113
Q

How could you make the external jugular vein prominent ?

A

Take a deep breath in makes the vein prominent

Valsalva maneuver

114
Q

What lies between the sternal heads of the sternocleidomastoid muscles?

A

Jugular notch of manubrium

115
Q

Where does the internal jugular vein lie?

A

Lesser supraclavicular fossa between the sternal and clavicular heads of the sternocleidomastoid muscle - overlies the end of the IJV

116
Q

What is the carotid sheath and where does it lie?

A

IJV + common carotid + vagus

Lies deep to the inferior half of the sternocleidomastoid muscle

117
Q

What lies deep to the superior half of the sternocleidomastoid muscle?

A

Cervical plexus

118
Q

What muscles lie superior and inferior to the hyoid bone

A

Suprahyoid muscles

  • Mylohyoid muscle
  • geniohyoid muscle
  • stylohyoid muscle
  • digastric muscle - ant. and post. belly

Infrahyoid muscles

  • sternohyoid
  • omohyoid
  • sternothyroid
  • thyrothyroid
119
Q

Where does the thyroid gland lie relative to the trachea and larynx?

A

Anterolaterally

R and L lobes

120
Q

What vertebrae level does the thyroid gland lie?

A

C5-T1

121
Q

What lies in the anterior neck
put in order

thyroid
thyroid cartilage
trachae
cricoid cartilage

A

Superiorly

  1. Thyroid cartilage
  2. Cricoid cartilage
  3. Thyroid gland
  4. Trachea
122
Q

What is the cricoid cartilage?

A

Only complete ring of cartilage around he trachea
Sits inferior to the thyroid cartilage and superior to the thyroid
IT IS NOT THE 1ST TRACHEAL RING

123
Q

What is the arterial blood supply to the thyroid? And where do they arise from?

A
  1. Superior thyroid artery- arises from external carotid artery
  2. Inferior thyroid artery - arises from subclavian artery (branches of thyrocervical trunks
124
Q

What is the venous drainage of the thyroid?

A

3 Pairs of thyroid veins usually rain the thyroid plexus of veins on the anterior surface of the thyroid gland and trachae

  1. Superior thyroid vein - drains into internal jugular vein
  2. Middle thyroid vein - drains into internal jugular vein
  3. Inferior thyroid vein - drains into the brachiocephalic veins posterior to the manubrium
125
Q

What is the nervous innervation to the thyroid?

A

Branches of the vagus

  1. Superior laryngeal Nerve
    - internal branch
    - external branch
  2. Left recurrent laryngeal nerve
126
Q

What is the anatomical position of the larynx and at what vertebrae levels?

A

Complex organ of voice production

Anterior neck at level C3-C6

Connects oropharynx with trachea

127
Q

What is the most important function of the larynx?

A

Guard the air passage, especially during swallowing, where it serves as a sphincter/valve of the lower respiratory tract, thus maintaining a patient airway

128
Q

What is the laryngeal skeleton composed of?

A

9 cartilages joined together by ligaments and membranes

  • 3 cartilages are single: thyroid, cricoid, epiglottic
  • 3 cartilages are paired: arytenoid, corniculate, and cuneiform (posterior aspect)
129
Q

Which vertebral bodies lies the thyroid cartilage?

A

C4

130
Q

What does the median plan of the thyroid cartilage form?

A

Laryngeal prominence (Adam’s apple)

131
Q

How does the thyroid cartilage attach to the hyoid bone?

A
  • Thyrohyoid membrane (superiorly)

- Thyrohyoid ligaments (medial and laterally)

132
Q

How does the thyroid cartilage articular with the cricoid cartilage?

A

Inferior horn of the thyroid cartilage articulates with the lateral surface of the cricoid cartilage at the cricothyroid joints

133
Q

What is the posterior and anterior surfaces of the cricoid cartilages called?

A

Posterior: lamina
Anterior: arch

134
Q

What surrounds the laryngeal ventricle?

A

Laryngeal ventricle

- recesses extending laterally from the middle part of the laryngeal cavity between the vestibular and vocal folds

135
Q

What are the vocal folds?

A

True vocal cords

Control sound production

136
Q

What is the action of the platysma muscle?

A

Draws corners of the mouth inferiorly and widens it

137
Q

Where does the platysma muscle arise from?

A

Arises in subcutaneous tissue covering the superior parts of the deltoid and pectolaris major and sweeps superiomedially over the clavicle into the inferior border of the mandible