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A&P2 > Test 3: Respiratory and Urinary Systems > Flashcards

Test 3: Respiratory and Urinary Systems Flashcards

1
Q

Respiratory is a term used to refer what?

A

ventilation of the lungs (breathing)
-In other contexts it can be used to refer to part of cellular metabolism

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2
Q

Respiratory System Functions

A
  1. Gas exchange: O_2 and CO_2 exchanged between blood and air
  2. Communication: speech and other vocalizations
  3. Olfaction: sense of smell
  4. Acid-Base balance: influences pH of body fluids by eliminating CO_2
  5. Blood pressure regulation: by helping in synthesis of angiotensin II
  6. Blood and lymph flow: breathing creates pressure gradients between thorax and abdomen that promote flow of lymph and blood
  7. Blood filtration: lungs filter small clots
  8. Expulsion of abdominal contents: breath-holding assists in urination, defecation, and childbirth(Valsalva maneuver)
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3
Q

Respiratory System Principal Organs

A
  • nose
  • pharynx
  • larynx
  • trachea
  • bronchi
  • lungs
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4
Q

Alveoli General Anatomy/ Function

A

-Incoming air stops in the alveoli
-Millions of thin-walled, microscopic air sacs
Exchanges gases with the bloodstream through the alveolar wall, and then flows back out

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5
Q

Conducting Zone

A
  • Includes those passages that serve only for airflow
  • No gas exchange
  • Nostrils through major bronchioles
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6
Q

Respiratory Zone

A

-Consists of alveoli and other gas exchange regions

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7
Q

Upper Respiratory Tract

A

—in head and neck
-Nose through larynx

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8
Q

Lower respiratory tract

A

—organs of the thorax
-Trachea through lungs

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9
Q

The Nose: Structure/ Function

A

Structure:

  • Nose extends from nostrils (nares) to posterior nasal apertures (choanae)—posterior openings
  • Facial part is shaped by bone and hyaline cartilage
  • Superior half: nasal bones and maxillae
  • Inferior half: lateral and alar cartilages
  • Ala nasi: flared portion at lower end of nose shaped by alar cartilages and dense connective tissue

Function:

  • Warms, cleanses, and humidifies inhaled air
  • Detects odors
  • Serves as a resonating chamber that amplifies voice
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10
Q

Nasal fossae

A

right and left halves of nasal cavity

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11
Q

Nasal septum

A

=Divides nasal cavity

  • Composed of bone and hyaline cartilage
  • Vomer forms inferior part
  • Perpendicular plate of ethmoid forms superior part
  • Septal cartilage forms anterior part

=Roof and floor of nasal cavity

  • Ethmoid and sphenoid bones form the roof
  • Hard palate forms floor
  • Separates the nasal cavity from the oral cavity and allows you to breathe while you chew food
  • Paranasal sinuses and nasolacrimal duct drain into nasal cavity
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12
Q

Vestibule

A

=beginning of nasal cavity; small, dilated chamber just -inside nostrils

  • Lined with stratified squamous epithelium
  • Vibrissae: stiff guard hairs that block insects and debris from entering nose
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13
Q

Nose Posterior Area

A

-Posteriorly the nasal cavity expands into a larger chamber with not much open space

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14
Q

Nasal Conchae

A

=Chamber behind vestibule is occupied by three folds of tissue

Structure:

  • Superior, middle, and inferior nasal conchae (turbinates)
  • Project from lateral walls toward septum
  • Meatus—narrow air passage beneath each concha
  • Narrowness and turbulence ensure that most air contacts mucous membranes
  • *Function:**
  • Cleans, warms, and moistens the air
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15
Q

Olfactory epithelium

A

=detects odors

  • *Structure:**
  • Covers a small area of the roof of the nasal fossa and adjacent parts of the septum and superior concha
  • Ciliated pseudostratified columnar epithelium

Function:
Immobile cilia on sensory cells bind odorant molecules

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16
Q

Respiratory epithelium

A

=lines rest of nasal cavity except vestibule

  • Ciliated pseudostratified columnar epithelium with goblet cells
  • Cilia are motile
  • Goblet cells secrete mucus and cilia propel the mucus posteriorly toward pharynx
  • Swallowed into digestive tract
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17
Q

Erectile tissue (swell body)

A

=AKA Swell Body

  • extensive venous plexus in epithelium of inferior concha
  • Every 30 to 60 minutes, tissue on one side swells with blood
  • Restricts airflow through that fossa, so most air directed through other nostril
  • Allows engorged side time to recover from drying
  • Preponderant flow of air shifts between the right and left nostrils once or twice an hour
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18
Q

Pharanyx

A

AKA throat
=muscular funnel extending about 5 in. from the choanae to the larynx

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19
Q

Pharynx: 3 Regions

A
  1. Nasopharynx
    - Posterior to nasal apertures and above soft palate
    - Receives auditory tubes and contains pharyngeal tonsil
    - 90* downward turn traps large particles (>10 m)
  2. Oropharynx
    - Space between soft palate and epiglottis
    - Contains palatine tonsils

3.Laryngopharynx
Epiglottis to cricoid cartilage
Esophagus begins at that point

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20
Q

Pharynx (and regions) Function

A
  • Nasopharynx passes only air and is lined by pseudostratified columnar epithelium
  • Oropharynx and laryngopharynx pass air, food, and drink and are lined by stratified squamous epithelium
  • Muscles of the pharynx assist in swallowing and speech
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21
Q

Larynx: General Structure/ Function

A

AKA Voice Box

  • cartilaginous chamber about 4 cm (1.5 in.) long
  • Primary function is to keep food and drink out of the airway
  • In several animals it has evolved the additional role of phonation—the production of sound
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22
Q

Epiglotties

A

=flap of tissue that guards the superior opening of the larynx

  • At rest, stands almost vertically
  • During swallowing, extrinsic muscles of larynx pull larynx upward
  • Tongue pushes epiglottis down to meet it
  • Closes airway and directs food to esophagus behind it
  • Vestibular folds of the larynx play greater role in keeping food and drink out of the airway
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23
Q

Larynx Structure: Cartilages

A

=Nine cartilages make up framework of larynx

  • First three are solitary and relatively large:
    1. Epiglottic cartilage: spoon-shaped supportive plate in epiglottis; most superior one
    2. Thyroid cartilage: largest, laryngeal prominence (Adam’s apple); shield-shaped
  • Testosterone stimulates growth, larger in males
    3. Cricoid cartilage: connects larynx to trachea, ring-like
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24
Q

First 3 Cartliages in Larynx

A
  1. Epigolottic Cartliage
  2. Thyroid Cartliage
  3. Cricoid Cartliage
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25
Q

3 Smaller, Paired Cartliages in Larynx

A
  1. Arytenoid cartilages (2): posterior to thyroid cartilage
  2. Corniculate cartilages (2): attached to arytenoid cartilages like a pair of little horns
  3. Cuneiform cartilages (2): support soft tissue between arytenoids and epiglottis
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26
Q

Larynx Structure: Ligaments

A

=Ligaments suspends larynx from hyoid and hold it together

  • Types:
    1. Thyrohyoid ligament suspends it from hyoid
    2. Cricotracheal ligament suspends trachea from larynx
    3. Intrinsic ligaments hold laryngeal cartilages together
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27
Q

Larynx Structure: Interior Wall

A

=Interior wall has two folds on each side that extend from thyroid cartilage in front to arytenoid cartilages in back
-Superior vestibular folds
-Play no role in speech
-Close the larynx during swallowing
Inferior vocal cords
-Produce sound when air passes between them
-Contain vocal ligaments
-Covered with stratified squamous epithelium
-Suited to endure vibration and contact
-Glottis—the vocal cords and the opening between them

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28
Q

Glottis

A

the vocal cords and the opening between them

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29
Q

Larynx Structure: Walls Muscle

A

=Walls of larynx are quite muscular

  • Deep intrinsic muscles operate the vocal cords
  • Superior extrinsic muscles connect larynx to hyoid bone
  • Elevate the larynx during swallowing
  • Infrahyoid group
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30
Q

Larynx Structure: Intrinsic Muscles

A

=Intrinsic muscles control vocal cords

  • Pull on corniculate and arytenoid cartilages causing cartilages to pivot
  • Abduct or adduct vocal cords, depending on direction of rotation
  • Air forced between adducted vocal cords vibrates them producing high-pitched sound when cords are taut
  • Produces lower-pitched sound when cords are more slack
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31
Q

Larynx: Male vs Female

A
  • Adult male vocal cords, when compared to female cords
  • Usually longer and thicker
  • Vibrate more slowly
  • Produce lower-pitched sound
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32
Q

Larynx Loudness

A

determined by the force of air passing between the vocal cords

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33
Q

Larynx Crude Sounds

A

Vocal cords produce crude sounds that are formed into words by actions of pharynx, oral cavity, tongue, and lips

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34
Q

Trachea: Structure

A

=Trachea (windpipe)—a rigid tube about 12 cm (4.5 in.) long and 2.5 cm (1 in.) in diameter

  • Anterior to esophagus
  • Supported by 16 to 20 C-shaped rings of hyaline cartilage that reinforce trachea and prevent collapse during inhalation
  • Opening in rings faces posteriorly toward esophagus
  • Trachealis muscle spans opening in rings
  • Gap in C allows room for the esophagus to expand as swallowed food passes by
  • Contracts or relaxes to adjust airflow
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35
Q

Trachea Structure: Inner Lining

A

=Inner lining of trachea is ciliated pseudostratified columnar epithelium

  • Composed mainly of mucus-secreting cells, ciliated cells, and stem cells
  • Mucociliary escalator: mechanism for debris removal
  • Mucus traps inhaled particles
  • Upward beating cilia drives mucus toward pharynx where it is swallowed
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36
Q

Trachea Structure: Middle Tracheal Layer

A

=connective tissue beneath the tracheal epithelium
-Contains lymphatic nodules, mucous and serous glands, and the tracheal cartilages

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37
Q

Trachea Structure: Adventitia

A

=outermost layer of trachea
-Fibrous connective tissue that blends into adventitia of other organs of mediastinum

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38
Q

Trachea Structure: Right & Left Main Bronchi

A
  • Trachea forks at level of sternal angle
  • Carina: internal medial ridge in the lowermost tracheal cartilage
  • Directs the airflow to the right and left
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39
Q

Tracheostomy

A

=to make a temporary opening in the trachea and insert a tube to allow airflow

  • Prevents asphyxiation due to upper airway obstruction
  • Inhaled air bypasses the nasal cavity and is not humidified
  • If left for long, will dry out mucous membranes of respiratory tract
  • Become encrusted and interfere with clearance of mucus from tract, thereby promoting infection
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40
Q

Lung Structure: Bronchial Tree

A
  • Base: broad concave portion resting on diaphragm
  • Apex: tip that projects just above the clavicle
  • Costal surface: pressed against the ribcage
  • Mediastinal surface: faces medially toward the heart
  • Hilum—slit through which the lung receives the main bronchus, blood vessels, lymphatics, and nerves
  • These structures near the hilum constitute the root of the lung
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41
Q

Lung Structure: Bronchial Tree: right vs left AND space within ribcage

A

=Lungs are crowded by adjacent organs; they neither fill the entire ribcage, nor are they symmetrical

  1. Right lung
    - Shorter than left because liver rises higher on the right
    - Has three lobes—superior, middle, and inferior—separated by horizontal and oblique fissure
  2. Left lung
    - Tall and narrow because the heart tilts toward the left and occupies more space on this side of mediastinum
    - Has indentation—cardiac impression
    - Has two lobes—superior and inferior separated by a single oblique fissure
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42
Q

The bronchial tree and segments

A

=a branching system of air tubes in each lung
-From main bronchus to 65,000 terminal bronchioles

  1. Main (Primary)
  2. Lobar (Secondary)
  3. Lobar (Tertiary)
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43
Q

Main (Primary) Bronchi: Left & Right

A

=supported by C-shaped hyaline cartilage rings

1.Right
-Rt. main bronchus is a branch 2 to 3 cm long, arising from fork of trachea
-Right bronchus slightly wider and more vertical than left
Aspirated (inhaled) foreign objects lodge in the right main bronchus more often than in the left

2.Left
-Lt. main bronchus is about 5 cm long
Slightly narrower and more horizontal than the right

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44
Q

Lobar (Secondary) Bronchi

A

=supported by crescent-shaped cartilage plates
Three rt. lobar (secondary) bronchi: superior, middle, and inferior
One to each lobe of the right lung
Two lt. lobar bronchi: superior and inferior
One to each lobe of the left lung

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45
Q

Segmental (Tertiary) Bronchi

A

=supported by crescent-shaped cartilage plates

  • 10 on right, 8 on left
  • Bronchopulmonary segment: functionally independent unit of the lung tissue
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46
Q

Bronchopulmonary segment

A

On the Segmental Bronchi
-functionally independent unit of the lung tissue

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47
Q

Bronchi Tissue Type

A

=are lined with ciliated pseudostratified columnar epithelium

  • Cells grow shorter and the epithelium thinner as we progress distally
  • Lamina propria has an abundance of mucous glands and lymphocyte nodules (mucosa-associated lymphoid tissue, MALT)
  • Positioned to intercept inhaled pathogens
  • All divisions of bronchial tree have a large amount of elastic connective tissue
  • Contributes to the recoil that expels air from lungs
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48
Q

Bronchial Tree Structure/ Function: Mucosa

A

=Mucosa has a well-developed layer of smooth muscle
-Muscularis mucosae contracts or relaxes to constrict or dilate the airway, regulating airflow

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49
Q

Bronchial Tree Structure/ Function: Pulmonary Artery

A

=Pulmonary artery branches closely follow the bronchial tree on their way to the alveoli

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50
Q

Bronchial Tree Structure/ Function: Bronchial Artery

A

=Bronchial artery services bronchial tree with systemic blood
-Arises from the aorta

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51
Q

Bronchioles Structure: Tissue Types/ Cilia

A

-1 mm or less in diameter
-Pulmonary lobule: portion of lung ventilated by one bronchiole
-Have ciliated cuboidal epithelium
-Well-developed layer of smooth muscle
-Divides into 50 to 80 terminal bronchioles
-Final branches of conducting zone
-Measure 0.5 mm or less in diameter
-Have no mucous glands or goblet cells
-Have cilia that move mucus draining into them back
by mucociliary escalator
-Each terminal bronchiole gives off two or more
smaller respiratory bronchioles

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52
Q

Respiratory Bronchioles

A
  • Have alveoli budding from their walls
  • Considered the beginning of the respiratory zone since alveoli participate in gas exchange
  • Divide into 2 to 10 alveolar ducts
  • End in alveolar sacs: clusters of alveoli arrayed around a central space called the atrium
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53
Q

Alveoli

A

=150 million alveoli in each lung, providing about 70 m^2 of surface for gas exchange

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54
Q

Alveoli Structure: Cells of the aveolus

A
  • Squamous (type I) alveolar cells
  • Thin, broad cells that allow for rapid gas diffusion between alveolus and bloodstream
  • Cover 95% of alveolus surface area
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55
Q

Alveoli: Great (type II) Alveolar Cells

A
  • Round to cuboidal cells that cover the remaining 5% of alveolar surface
  • Repair the alveolar epithelium when the squamous (type I) cells are damaged
  • Secrete pulmonary surfactant
  • A mixture of phospholipids and proteins that coats the alveoli and prevents them from collapsing during exhalation
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56
Q

Alveoli: Alveolar Macrophages

A

AKA Dust cells

  • Most numerous of all cells in the lung
  • Wander the lumens of alveoli and the connective tissue between them
  • Keep alveoli free from debris by phagocytizing dust particles
  • 100 million dust cells die each day as they ride up the mucociliary escalator to be swallowed and digested with their load of debris
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57
Q

Alveoli Structure

A

Each alveolus surrounded by a basket of capillaries supplied by the pulmonary artery
Respiratory membrane—thin barrier between the alveolar air and blood

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58
Q

Aveoli: Respiratory Membrane Structure

A
  • Squamous alveolar cells
  • Endothelial cells of blood capillary
  • Their shared basement membrane
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59
Q

Alveoli Function

A
  • Gases diffuse too slowly through liquid to sufficiently aerate the blood
  • Alveoli are kept dry by absorption of excess liquid by blood capillaries
  • Lungs have a more extensive lymphatic drainage than any other organ in the body
  • Low capillary blood pressure also prevents rupture of the delicate respiratory membrane
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60
Q

Pulmonary Ventilation

A

AKA: breathing
-consists of a repetitive cycle of inspiration (inhaling) and expiration (exhaling)

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61
Q

Respiratory Cycle

A

=one complete inspiration and expiration

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62
Q

Quiet Respiration

A

while at rest, effortless, and automatic

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63
Q

Forced Respiration

A

deep, rapid breathing, such as during exercise

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64
Q

Flow of air & pressure

A
  • Flow of air in and out of lung depends on a pressure difference between air within lungs and outside body
  • Respiratory muscles change lung volumes and create differences in pressure relative to the atmosphere
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65
Q

Respiratory Muscle: Diaphragm

A
  • Prime mover of respiration
  • Contraction flattens diaphragm, enlarging thoracic cavity and pulling air into lungs
  • Relaxation allows diaphragm to bulge upward again, compressing the lungs and expelling air
  • Accounts for two-thirds of airflow
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66
Q

Neural control of breathing

A

-No autorhythmic pacemaker cells for respiration, as in the heart
-Exact mechanism for setting the rhythm of respiration remains unknown
-Breathing depends on repetitive stimulation of skeletal muscles from brain and will cease if spinal cord is severed high in neck
-Skeletal muscles require nervous stimulation
Interaction of multiple respiratory muscles requires coordination

67
Q

Brainstem Respiratory Centers

A

-Automatic, unconscious cycle of breathing is controlled by three pairs of respiratory centers in the reticular formation of the medulla oblongata and the pons

68
Q

Respiratory Network in Medulla

A
  1. Ventral respiratory group (VRG)
    - Primary generator of the respiratory rhythm
    - In quiet breathing (eupnea), inspiratory neurons fire for about 2 seconds
    - Expiratory neurons in eupnea fire for about 3 seconds allowing inspiratory muscles to relax
    - Produces a respiratory rhythm of 12 breaths per minute
  2. Dorsal respiratory group (DRG)
    - Modifies the rate and depth of breathing
    - Receives influences from external sources
69
Q

Respiratory Network in Pons

A
  1. Pontine respiratory group (PRG)
    - Modifies rhythm of the VRG by outputs to both the VRG and DRG
    - Adapts breathing to special circumstances such as sleep, exercise, vocalization, and emotional responses
70
Q

Hyperventilation

A

-anxiety-triggered state in which breathing is so rapid that it expels CO_2 from the body faster than it is produced

71
Q

Hyperventilation Mechanism

A
  • As blood CO_2 levels drop, the pH rises causing the cerebral arteries to constrict
  • This reduces cerebral perfusion which may cause dizziness or fainting
  • Can be brought under control by having the person rebreathe the expired CO_2 from a paper bag
72
Q

Respiratory Centers: Central & Peripheral Input Types (Receptors)

A

1.Central Chemoreceptors
2.Peripheral Chemoreceptors
3.Stretch Receptors
4.Irritant Receptors
5.

73
Q

Central Chemoreceptors

A

=brainstem neurons that respond to changes in pH of cerebrospinal fluid

  • pH of cerebrospinal fluid reflects the CO_2 level in the blood
  • By regulating respiration to maintain stable pH, respiratory center also ensures stable CO_2 level in blood
74
Q

Peripheral Receptors

A

=located in the carotid and aortic bodies of the large arteries above the heart
-Respond to the O_2 and CO_2 content and the pH
of blood

75
Q

Stretch Receptors

A

=found in the smooth muscles of bronchi and bronchioles, and in the visceral pleura
-Respond to inflation of the lungs
-Inflation (Hering-Breuer) reflex: triggered by
excessive inflation
-Protective reflex that inhibits inspiratory neurons
and stops inspiration

76
Q

Irritant Receptors

A

=nerve endings amid the epithelial cells of the airway

  • Respond to smoke, dust, pollen, chemical fumes, cold air, and excess mucus
  • Trigger protective reflexes such as bronchoconstriction, shallower breathing, breath-holding (apnea), or coughing
77
Q

Voluntary Control of breathing

A

=Voluntary control over breathing originates in the motor cortex of frontal lobe of the cerebrum
-Sends impulses down corticospinal tracts to respiratory neurons in spinal cord, bypassing brainstem

78
Q

Voluntary Control Limits

A

Breaking point: when CO_2 levels rise to a point where automatic controls override one’s will

79
Q

Newborn Baby: Water by Weight

A

75% Water

80
Q

Young Men/ Women: Water by Weight

A

55-60% Water
Women is slightly less

81
Q

Obese/ Elderly People: Water by Weight

A

45%

82
Q

Total body water of a 70 kg (150lb) Young Male

A

About 40 L

83
Q

Major Fluid Compartments of the body

A

=65% intracellular fluid (ICF)
=35% extracellular fluid (ECF)
-25% tissue (interstitial) fluid
-4.8% blood plasma and lymphatic fluid
-2% transcellular fluid “catch-all” category
-Cerebrospinal, synovial, peritoneal, pleural, and
pericardial fluids
-Vitreous and aqueous humors of the eye
-Bile, and fluids of the digestive, urinary, and
reproductive tracts

84
Q

Fluid Compartments & Movement

A

-Fluid continually exchanged between compartments
-Water moves by osmosis
-Because water moves so easily through membranes, osmotic gradients never last long
-If imbalance arises, osmosis restores balance within seconds, so the intracellular and extracellular osmolarity are equal
-If osmolarity of the tissue fluid rises, water moves
out of the cell
-If it falls, water moves in

85
Q

Osmosis, Solutes, & Electrolytes

A

=Osmosis from one fluid compartment to another is determined by the relative concentrations of solutes in each compartment
-Electrolytes: the most abundant solute particles, by
far
-Sodium salts in ECF
-Potassium salts in ICF
-Electrolytes play the principal role in governing the body’s water distribution and total water content

86
Q

Electrolyte Balance

A
  • Great differences between electrolyte concentrations of blood plasma and intracellular fluid (ICF)
  • Have the same osmolarity (300 mOsm/L)
  • Concentrations in tissue fluid (ECF) differ only slightly from those in the plasma
87
Q

Major Electrolytes

A
  1. Sodium
  2. Potassium
  3. Chloride
  4. Calcium
  5. Magnesium
88
Q

Sodium: Functions

A

1.one of the principal ions responsible for the resting membrane potential
-Inflow of sodium through membrane gates is an
essential event in depolarizations that underlie nerve
and muscle function

2.Principal cation in ECF
-Sodium salts account for 90% to 95% of osmolarity
of ECF
-Most significant solute in determining total body
water and distribution of water among fluid
compartments
-Na^+ gradient is a source of potential energy for
cotransport of other solutes such as glucose,
potassium, and calcium
3.Na^+–K^+ pump
-Important means of generating body heat
-Na^+ gradient is a source of potential energy for
cotransport of other solutes such as glucose,
potassium, and calcium

89
Q

Potassium: Functions

A
  1. Produces (with sodium) the resting membrane potentials and action potentials of nerve and muscle cells
    - Most abundant cation of ICF
    - Greatest determinant of intracellular osmolarity and cell volume
  2. Na^+− K^+ pump
  3. Essential cofactor for protein synthesis and other metabolic processes
90
Q

Chloride: Functions

A
  • Most abundant anion in ECF
    1. Major contribution to ECF osmolarity
    2. Required for the formation of stomach acid (HCl)
    3. Chloride shift that accompanies CO_2 loading and unloading in RBCs
    4. Major role in regulating body pH
91
Q

Calcium: Functions

A
  1. Lends strength to skeleton
  2. Activates sliding filament mechanism of muscle contraction
  3. Serves as a second messenger for some hormones and neurotransmitters
  4. Activates exocytosis of neurotransmitters and other cellular secretions
  5. Essential factor in blood clotting
92
Q

Magnesium: Functions

A

-About 54% of Mg^(2+) is in bone; about 45% in intracellular fluid
1.Most intracellular Mg^(2+) is complexed with ATP
Mg^(2+) serves as a cofactor for enzymes, transporters, and nucleic acids
2.Homeostasis
-Blood levels of Mg^(2+)
Intestinal absorption from food is regulated by
vitamin D
-Mg^(2+) is lost in feces and urine
-Ascending limb of nephron loop can reabsorb
Mg^(2+) and mainly determines the extent of
retention or loss
-Parathyroid hormone governs the rate of
reabsorption

93
Q

Excretion

A

separating wastes from body fluids and eliminating them

94
Q

Excretion: Four body systems

A

1.Respiratory system
CO_2, small amounts of other gases, and water
2.Integumentary system
Water, inorganic salts, lactic acid, urea in sweat
3.Digestive system
Water, salts, CO_2, lipids, bile pigments, cholesterol, and other metabolic waste
4.Urinary system
Many metabolic wastes, toxins, drugs, hormones, salts, H^+, and water

95
Q

Kidney Functions

A
  1. Filter blood and excrete toxic metabolic wastes
  2. Regulate blood volume, pressure, and osmolarity
  3. Regulate electrolytes and acid-base balance
  4. Secrete erythropoietin, which stimulates the production of red blood cells
  5. Help regulate calcium levels by participating in calcitriol synthesis
  6. Clear hormones from blood
  7. Detoxify free radicals
  8. In starvation, they synthesize glucose from amino acids
96
Q

Nitrogenous Wastes: Typees

A
  1. Urea formation
    - Proteins amino acids  NH_2 removed  forms ammonia,
    - Liver converts ammonia to urea
  2. Uric acid
    - Product of nucleic acid catabolism
  3. Creatinine
    - Product of creatine phosphate catabolism
  4. Blood urea nitrogen (BUN)—level of nitrogenous waste in blood
    - Normal concentration of blood urea is 10 to 20 mg/dL
    - Azotemia: elevated BUN
    - May indicate renal insufficiency
    - Uremia: syndrome of diarrhea, vomiting, dyspnea, and cardiac arrhythmia stemming from the toxicity of nitrogenous waste
    - Treatment—hemodialysis or organ transplant
97
Q

Waste

A

any substance that is useless to the body or present in excess of the body’s needs

98
Q

Metabolic Waste

A

waste substance produced by the body

99
Q

Azotemia

A

Elevated BUN; May indicate renal insufficiency

100
Q

Uremia

A

syndrome of diarrhea, vomiting, dyspnea, and cardiac arrhythmia stemming from the toxicity of nitrogenous waste

101
Q

Kidney: Position, Weight, Size

A
  • Lie against posterior abdominal wall
  • Right kidney is slightly lower due to large right lobe of liver
  • Rib 12 crosses the middle of the left kidney
  • Retroperitoneal along with ureters, urinary bladder, renal artery and vein, and adrenal glands
102
Q

Kidney: Shape & Size

A

-About the size of a bar of bath soap
-Lateral surface is convex, and medial is concave with a slit, called the hilum
-Receives renal nerves, blood vessels, lymphatics,
and ureter

103
Q

Kidney: 3 Protective Tissue Coverings

A
  1. Renal fascia immediately deep to parietal peritoneum
    - Binds it to abdominal wall
  2. Perirenal fat capsule: cushions kidney and holds it into place
  3. Fibrous capsule encloses kidney protecting it from trauma and infection
    - Collagen fibers extend from fibrous capsule to renal fascia
    - Still drop about 3 cm when going from lying down to standing up
    - Renal parenchyma—glandular tissue that forms urine
104
Q

Renal parenchyma

A

glandular tissue that forms urine

105
Q

Renal Parenchyma: Two Zones

A
  1. Outer renal cortex
  2. Inner renal medulla
    - Renal columns—extensions of the cortex that project inward toward sinus
    - Renal pyramids—6 to 10 with broad base facing cortex and renal papilla facing sinus
106
Q

Lobe of kidney

A

one pyramid and its overlying cortex

107
Q

Minor Calyx

A

cup that nestles the papilla of each pyramid; collects its urine

108
Q

Major Calyx

A

formed by convergence of 2 or 3 minor calyces

109
Q

Renal pelvis

A

formed by convergence of 2 or 3 major calyces

110
Q

Ureter

A

a tubular continuation of the pelvis that drains urine down to the urinary bladder

111
Q

Renal Circulation

A

Kidneys are only 0.4% of body weight, but receive about 21% of cardiac output (renal fraction)

112
Q

Renal Circulation Flow

A
  1. Renal Arteries
  2. Interlobar arteries: up renal columns, between pyramids
  3. .Arcuate arteries: over pyramids
  4. Cortical radiate arteries: up into cortex
  5. Branch into afferent arterioles: each supplying one nephron
  6. Glomerulus - ball of capillaries
  7. Efferent Arteries
  8. Peritubular Capilliaries (most efferent form here) OR vasa recta (a nework of blood vessels within the renal medullla)
  9. Cortical Radiate Veins (from pertiubular arteries) OR Arcuate Veins (from Vasa Recta)
  10. Arcuate Veins
  11. Interlobar Veins
  12. Renal Vein
  13. Inferior Vena Cava
113
Q

Peritubular Capillaries vs Vasa Recta

A

Efferemt Arteries either direct blood to:

  1. Peritublar Capillaries (most blood forms here)
  2. Vasa Recta: a nework of blood vessels within the renal medulla that directly flows into arcuate veins
114
Q

Label this diagram

A

A.Aorta

B.Renal Artery

C.Segmental Artery

D.Interlobar Artery

E.Arcualate Artery

F.Cortical Radiate Artery

G.Afferent Arteriole

H.Glomerulus

I.Efferent Arteriole

J.Vasa Recta

K.Pertibular Capillaries

L.Cortical Radiate Vein

M.Arcuate Vein

N.Interlobar Vein

O.Renal Vein

P.Inferior Vena Cava

115
Q

Nephron: # in Kidneys

A

Each kidney has about 1.2 million nephrons

116
Q

Nephron: 2 Principal Parts

A
  1. Renal corpuscle: filters the blood plasma
  2. Renal tubule: long, coiled tube that converts the filtrate into urine
117
Q

Renal Corpsucle: Parts &

A

=glomerulus and a two-layered glomerular capsule that encloses glomerulus

  1. –Parietal (outer) layer of glomerular capsule is simple squamous epithelium
  2. –Visceral (inner) layer of glomerular capsule consists of elaborate cells called podocytes that wrap around the capillaries of the glomerulus

**Capsular space separates the two layers of glomerular capsule

118
Q

Juxtamedullary

A

–15% of all nephrons

–Very long nephron loops, maintain salinity gradient in the medulla and help conserve water

–Efferent arterioles branch into vasa recta around long nephron loop

119
Q

Cortical Nephrons

A

–85% of all nephrons

–Short nephron loops

–Efferent arterioles branch into peritubular capillaries around PCT and DCT

120
Q

Renal Plexus & Innervation

A

Nerves and ganglia wrapped around each renal artery

1.Carries sympathetic innervation from the abdominal aortic plexus

  • Stimulation reduces glomerular blood flow and rate of urine production
  • Respond to falling blood pressure by stimulating the kidneys to secrete renin, an enzyme that activates hormonal mechanisms to restore blood pressure

2.Kidneys also receive parasympathetic innervation of unknown function

121
Q

Urine Formation: Glomerular Filtration

A

•Kidneys convert blood plasma to urine in four stages

  1. Glomerular filtration
  2. Tubular reabsorption
  3. Tubular secretion
  4. Water conservation
122
Q

Glomerular Filtrate

A

=the fluid in the capsular space

–Similar to blood plasma except that it has almost no protein

123
Q

Tubular Fluid

A

=fluid from the proximal convoluted tubule through the distal convoluted tubule

–Substances have been removed or added by tubular cells

124
Q

Urine

A

=fluid that enters the collecting duct

–Undergoes little alteration beyond this point except for changes in water content

125
Q

The Glomerular Filtation Membrane

A

•Glomerular filtration—a special case of capillary fluid exchange in which water and some solutes in the blood plasma pass from the capillaries of the glomerulus into the capsular space of the nephron

126
Q

The Glomular Filtration Membrane

A

•Almost any molecule smaller than 3 nm can pass freely through the filtration membrane

–Water, electrolytes, glucose, fatty acids, amino acids, nitrogenous wastes, and vitamins

•Some substances of low molecular weight are bound to the plasma proteins and cannot get through the membrane

–Most calcium, iron, and thyroid hormone

Unbound fraction passes freely into the filtrate

127
Q

The Glomular Filtation Membrane: Kidney Infection/ Disance Runners

A

•Kidney infections and trauma can damage the filtration membrane and allow albumin or blood cells to filter

–Proteinuria (albuminuria): presence of protein in urine

–Hematuria: presence of blood in the urine

•Distance runners and swimmers often experience temporary proteinuria or hematuria

–Prolonged, strenuous exercise reduces profusion of kidney

–Glomerulus deteriorates under prolonged hypoxia

128
Q

Tubular Reaborbtion

A

•process of reclaiming water and solutes from tubular fluid and returning them to blood

129
Q

Urine Formation: Tubular Reabsorbtion

A

•PCT reabsorbs about 65% of glomerular filtrate, removes some substances from blood, and secretes them into tubular fluid for disposal in urine

–Prominent microvilli and great length

–Abundant mitochondria provide ATP for active transport

–PCTs alone account for about 6% of one’s resting ATP and calorie consumption

130
Q

Tubular Reabsorbtion: Two Routes

A

1.Transcellular route

•Substances pass through cytoplasm of PCT epithelial cells and out their base

2.Paracellular route

  • Substances pass between PCT cells
  • Junctions between epithelial cells are leaky and allow significant amounts of water to pass through
  • Solvent drag—water carries a variety of dissolved solutes with it
  • Reabsorbed fluid is ultimately taken up by peritubular capillaries
131
Q

Tubular Reabsorbtion: Sodium

A

•Sodium reabsorption is key

–Creates an osmotic and electrical gradient that drives the reabsorption of water and other solutes

–Na^+ is most abundant cation in filtrate

–Creates steep concentration gradient that favors its diffusion into epithelial cells

–Two types of transport proteins in the apical cell surface are responsible for sodium uptake

  • Symports that simultaneously bind Na^+ and another solute such as glucose, amino acids, or lactate
  • Na^+–H^+ antiport that pulls Na^+ into the cell while pumping out H^+ into tubular fluid

–Sodium is prevented from accumulating in epithelial cells by Na^+–K^+ pumps in the basal surface of the epithelium

•Pumps Na^+ out to extracellular fluid

–Na^+ is picked up by peritubular capillaries and returned to blood

–The Na^+–K^+ pumps (at the base) are examples of primary active transport – they use ATP

–The symports on the apical surface are examples of secondary active transport – they do not directly consume ATP, but are dependent on the primary transport Na^+–K^+ pumps at the base of the cell to establish the sodium concentration gradient

•Negative chloride ions follow the positive sodium ions by electrical attraction

–Various antiports in the apical cell membrane that absorb Cl^- in exchange for other anions they eject into the tubular fluid: K^+–Cl^- symport

132
Q

Tubular Reabsorbtion: Other molecules/ electrolyres

A
  • Potassium, magnesium, and phosphate ions diffuse through the paracellular route with water
  • Phosphate is also cotransported into the epithelial cells with Na^+
  • Some calcium is reabsorbed through the paracellular route in the PCT, but most Ca^(2+) reabsorption occurs later in the nephron
  • Glucose is cotransported with Na^+ by sodium–glucose transport (SGLT) proteins – normally all glucose is reabsorbed
  • Nitrogenous wastes

–Nephron reabsorbs about half of urea in tubular fluid

•Concentration remaining in blood is safe

–PCT (proximal convolute dtubule) reabsorbs uric acid, but later portions of the nephron secrete it

–Creatinine is not reabsorbed – it is passed in urine

133
Q
A
134
Q

Tubular Reabsorbtion: Facts

A
  • Each day, kidneys reduce 180 L of glomerular filtrate to 1 or 2 L of urine
  • Two-thirds of water in filtrate is reabsorbed in PCT
  • Reabsorption of solutes makes the tubule cells and tissue fluid hypertonic to tubular fluid

–Water follows solutes by osmosis through both paracellular and transcellular routes

•Transcellularly, water uses channels called aquaporins

–In PCT, water is reabsorbed at constant rate called obligatory water reabsorption

135
Q

Acquaporins

A

Channels within tubular reabsortion

136
Q

The Transport Maximum

A
  • The amount of solute that renal tubules can reabsorb is limited by the number of transport proteins in tubule cells’ membranes
  • If all transporters are occupied, any excess solute passes by and appears in urine
  • Transport maximum is reached when transporters are saturated
  • Each solute has its own transport maximum

–Any blood glucose level above 220 mg/dL results in glycosuria

137
Q

Uptake by the Peritubular Capillaries

A

•Peritubular capillaries reabsorb water and solutes that leave the basal surface of the tubular epithelium

Reabsorption occurs by osmosis and solvent drag

138
Q

3 Factors promote osmosis into the capillaries

A
  1. High interstitial fluid pressure due to accumulation of reabsorbed fluid in extracellular space
  2. Low blood hydrostatic pressure in peritubular capillaries due to narrowness of efferent arterioles
  3. High colloid osmotic pressure in blood due to presence of proteins that were not filtered
139
Q

Tubular Secretion

A

renal tubule extracts chemicals from capillary blood and secretes them into tubular fluid

140
Q

Turbular Secretion Purpose

A

1.Acid–base balance

•Secretion of varying proportions of hydrogen and bicarbonate ions helps regulate pH of body fluids

2.Waste removal

•Urea, uric acid, bile acids, ammonia, and a little creatinine are secreted into the tubule

3.Clearance of drugs and contaminants

•Examples include: morphine, penicillin, and aspirin

141
Q

The Nephron Loop: Function

A

•generate salinity gradient that enables collecting duct to concentrate the urine and conserve water

142
Q

Electrolyte reabsorption from filtrate

A

–Thick segment reabsorbs 25% of Na^+, K^+, and Cl^- in filtrate

•Ions leave cells by active transport and diffusion

–NaCl remains in the tissue fluid of renal medulla

–Water cannot follow since thick segment is impermeable

–Tubular fluid very dilute as it enters distal convoluted tubule

143
Q

The Distal Convulated Tubule Collecting Duct

A

•Fluid arriving in the DCT still contains about 20% of the water and 7% of the salts from glomerular filtrate

–If this were all passed as urine, it would amount to 36 L/day

•DCT and collecting duct reabsorb variable amounts of water and salt and are regulated by several hormones

–Aldosterone, atrial natriuretic peptide, ADH, and parathyroid hormone

144
Q

Cells in the DCT & Collecting Duct: 2 Types

A

1.Principal cells

  • Most numerous
  • Have receptors for hormones
  • Involved in salt and water balance

2.Intercalated cells

•Involved in acid–base balance by secreting H^+ into tubule lumen and reabsorbing K^+

145
Q

Urine Formation: Water Conservation

A
  • The kidney eliminates metabolic wastes from the body, but prevents excessive water loss
  • As the kidney returns water to the tissue fluid and bloodstream, the fluid remaining in the renal tubules passes as urine, and becomes more concentrated
146
Q

Collecting Duct

A
  • Collecting duct (CD) begins in the cortex where it receives tubular fluid from several nephrons
  • CD runs through medulla, and reabsorbs water, making urine up to four times more concentrated
  • Medullary portion of CD is more permeable to water than to NaCl
  • As urine passes through the increasingly salty medulla, water leaves by osmosis, concentrating urine
147
Q

How concentrated the urine becomes depends on______

A

body’s state of hydration

148
Q

Water Diuresis

A

•drinking large volumes of water will produce a large volume of hypotonic urine

–Cortical portion of CD reabsorbs NaCl, but it is impermeable to water

–Salt is removed from the urine but water stays in

-Urine concentration may be as low as 50 mOsm/L

149
Q

Dehydration leads to_____

A

=production of hypertonic urine

–Urine becomes scanty and more concentrated

–High blood osmolarity stimulates posterior pituitary to release ADH and then an increase in synthesis of aquaporin channels by renal tubule cells

–More water is reabsorbed by collecting duct

–Urine is more concentrated

150
Q

If BP is low in a dehydrated person___

A

=GFR will be low

–Filtrate moves more slowly and there is more time for reabsorption

–More salt removed, more water reabsorbed, and less urine produced

151
Q

Countercurrent Multiplier

A

•The ability of kidney to concentrate urine depends on salinity gradient in renal medulla

–Four times more salinity in the renal medulla than the cortex

***Nephron loop acts as countercurrent multiplier (Countercurrent system—formed by blood flowing in opposite directions in adjacent parallel capillaries)

  • Vasa recta—capillary branching off efferent arteriole in medulla , gives the salt back and does not subtract from the osmolarity of the medulla
  • Multiplier: continually recaptures salt and returns it to extracellular fluid of medulla which multiplies the osmolarity of adrenal medulla

–Countercurrent : because of fluid flowing in opposite directions in adjacent tubules of nephron loop

152
Q

Countercurrent Multiplier: Fluid downward & upward

A

1.Fluid flowing downward in descending limb

–Passes through environment of increasing osmolarity

–Most of descending limb very permeable to water but not to NaCl

–Water passes from tubule into the ECF leaving salt behind

–Concentrates tubular fluid to 1,200 mOsm/L at lower end of loop

2.Fluid flowing upward in ascending limb

–Impermeable to water

–Reabsorbs Na^+, K^+, and Cl^- by active transport pumps into ECF

–Maintains high osmolarity of renal medulla

–Tubular fluid becomes dilute: 100 mOsm/L at top of loop

153
Q

Counter Current Multiplier: Recycling Urea

A

•Recycling of urea adds to high osmolarity of deep medulla

–Lower end of collecting duct is permeable to urea but neither thick segment of loop nor DCT is permeable to urea

–Urea is continually cycled from collecting duct to the nephron loop and back

–Urea remains concentrated in the collecting duct and some of it always diffuses out into the medulla adding to osmolarity

154
Q

Renal Autoregulation: Tubuloglomerular Fedback

A

•glomerulus receives feedback on the status of downstream tubular fluid and adjusts filtration rate accordingly

–Regulates filtrate composition, stabilizes kidney performance, and compensates for fluctuations in blood pressure

–Juxtaglomerular apparatus: complex structure found at the end of the nephron loop where it has just reentered the renal cortex

–Loop comes into contact with the afferent and efferent arterioles at the vascular pole of the renal corpuscle

155
Q

Symphathetic Control: Renal Blood Vessels

A
  • Sympathetic nerve fibers richly innervate the renal blood vessels
  • Sympathetic nervous system and adrenal epinephrine constrict the afferent arterioles in strenuous exercise or acute conditions like circulatory shock
156
Q

Renin-Angiotensin-Adolsterone Mechanism: Renin

A
  • The renin-angiotensin-aldosterone mechanism is a system of hormones that helps control blood pressure and GFR (glomerular filtration rate)
  • In response to a drop in blood pressure, baroreceptors in carotid and aorta stimulate the sympathetic nervous system
  • Sympathetic fibers trigger release of renin by kidneys’ granular cells
  • Renin converts angiotensinogen, a blood protein, into angiotensin I
157
Q
A
158
Q

Renin–Angiotensin–Aldosterone Mechanism: Angiotensin

A
  • In lungs and kidneys, angiotensin-converting enzyme (ACE) converts angiotensin I to angiotensin II
  • Angiotensin II—active hormone that increases BP

–Potent vasoconstrictor raising BP throughout body

–Constricts efferent arteriole raising GFR despite low BP

–Lowers BP in peritubular capillaries enhancing reabsorption of NaCl and H_2 O

–Stimulates adrenal cortex to secrete aldosterone, which promotes Na^+ and H_2 O reabsorption in DCT and collecting duct

–Stimulates Na^+ and H_2 O reabsorption in PCT

–Stimulates posterior pituitary to secrete ADH which promotes water reabsorption by collecting duct

–Stimulates thirst

159
Q

Renin–Angiotensin–Aldosterone Mechanism: Adolsterone

A

•Aldosterone—the “salt-retaining hormone”

–Steroid secreted by the adrenal cortex

–Triggers for aldosterone secretion are:

  • When blood Na^+ concentration falls or
  • When K^+ concentration rises or
  • There is a drop in blood pressure ® renin release ® angiotensin II formation ® stimulates adrenal cortex to secrete aldosterone
160
Q

Adolsterone Functions

A

–Acts on thick segment of nephron loop, DCT, and cortical portion of collecting duct

  • Stimulates reabsorption of Na^+ and secretion of K^+
  • Water and Cl^- follow the Na^+
  • Net effect is that the body retains NaCl and water

–Helps maintain blood volume and pressure

  • Urine volume is reduced
  • Urine has an elevated K^+ concentration
161
Q

Natriuretic peptides

A

•secreted by atrial myocardium of the heart in response to high blood pressure

162
Q

Four actions result in the excretion of more salt and water in the urine

A

To reduce blood volume and pressure

  1. Dilates afferent arteriole, constricts efferent arteriole: ­ GFR
  2. Inhibits renin and aldosterone secretion
  3. Inhibits secretion of ADH
  4. Inhibits NaCl reabsorption by collecting duct
163
Q

Antidiuretic Hormone (ADH)

A

•secreted by posterior pituitary

–Dehydration, loss of blood volume, and rising blood osmolarity stimulate arterial baroreceptors and hypothalamic osmoreceptors

–This triggers release of ADH from the posterior pituitary

–ADH makes collecting duct more permeable to water

–Water in the tubular fluid reenters the tissue fluid and bloodstream rather than being lost in urine

164
Q

Parathyroid Hormone (PTH)

A

•secreted from parathyroid glands in response to calcium deficiency (hypocalcemia)

–Acts on PCT to increase phosphate excretion

–Acts on the thick segment of the ascending limb of the nephron loop, and on the DCT to increase calcium reabsorption

–Increases phosphate content and lowers calcium content in urine

–Because phosphate is not retained, calcium ions stay in circulation rather than precipitating into bone tissue as calcium phosphate

-PTH stimulates calcitriol synthesis by epithelial cells of the PCT

A&P2 (13 decks)

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