final Flashcards

1
Q

what are the 5 iono and osmotic regulation categories

A
  • osmoconformers
  • marine elasmobranchs
  • marine teleosts and chondrosteans
  • freshwater fishes and elasmobranchs
  • euryhaline and diadromous species
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2
Q

how do osmoconformers regulate

A
  • live in stable environments so dont need to regulate
  • are stenohaline
  • ionic concentration close to seawater (isosmotic)
  • some regulation through urine and slime
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3
Q

how do marine elasmobranchs regulate

A
  • concentration of ions ~1/2 of SW
  • osmolality slightly hyperosmotic
  • increase osmolality by increasing concentration of organic solutes in the extracellular fluids (urea and TMAO)
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4
Q

why dont marine elasmobranchs need to drink water

A

osmolality is slightly hyperosmotic so water diffuses into body

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5
Q

how are urea concentrations maintained in marine elasmobranchs

A
  • low gill permeability for this solute (phospholipid concentration)
  • presence of a urea transporter for active re-uptake at gills
  • special kidney tubules to reabsorb urea
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6
Q

what is the function of TMAO in marine elasmobranchs

A
  • increases osmolality
  • counteracts the damage urea does to proteins
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7
Q

how do marine elasmobranchs eliminate ions

A
  • divalent ions removed in urine (urine production very low)
  • Na+ and Cl- not eliminated at gills but at specialized organ called rectal gland
  • ion concentration in secretion twice that of body fluids
  • gills pH regulation
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8
Q

how do marine teleosts and chondrosteans regulate

A
  • ion concentration of plasma and ECF 1/3 of SW (hyposmotic)
  • gain ions and lose water
  • have to actively drink SW and use active ion transport to take up water (water follows ion movement)
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9
Q

how do marine teleosts and chondrosteans get rid of ions

A
  • gills and opercular epithelial tissues and sometimes skin of head have chloride cells
  • efflux of Na+ and Cl- occurs here
  • glomerular or aglomerular kidneys excrete divalent ions Mg2+ and SO42-
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10
Q

properties of chloride cells

A
  • mitochondria rich
  • on gills, opercular tissue, sometimes skin of head
  • basolateral membrane that is highly folded
  • tubule system similar to endoplasmic reticulum
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11
Q

summary of osmotic and ionic regulation in seawater teleosts

A
  • water loss over gills and skin
  • drink sea water
  • active excretion of monovalent ions via Cl- cells on gills
  • divalent ions lost in feces and urine
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12
Q

how do freshwater fish and elasmobranchs regulate

A
  • operate hyperosmotically
  • constantly gain water osmotically and lose ions by diffusion
  • lost ions replaced by food and uptake across the gills
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13
Q

two types of chloride cells in freshwater teleosts

A
  • alpha chloride cells
  • beta chloride cells
  • third type of mitochondrial rich cell now identified, thought to be a modified pavement cell
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14
Q

what are alpha chloride cells

A
  • found at the junction between primary and secondary lamellae
  • thought to undergo differentiation when FW fish migrate to SW
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15
Q

what are beta chloride cells

A
  • found in the open area between secondary lamellae and sometimes on secondary lamellae especially if water is soft
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16
Q

what are peanut agglutinin cells

A
    • or - (move different ions)
  • currently debate on which cells are which
    • function in Cl- uptake/bicarbonate excretion
    • function in Na+ uptake/acid excretion
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17
Q

important difference between freshwater and saltwater fish regulation

A
  • in freshwater fish the same cells are involved in regulating pH and ions
  • FW fish have a much higher urine flow to eliminate water
  • must ensure they lose as few ions as possible in urine
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18
Q

how do FW fish prevent ion loss through urine

A
  • glomerular filtration
  • water enters proximal tubule then distal tubule
  • ions are able to leave distal tubule and re enter body but water can’t follow bc its impermeable
  • water goes to bladder
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19
Q

how do euryhaline fish regulate

A
  • live in estuarine and intertidal environments
  • have ability to cover over their CC with pavement cells to minimize ion loss in hypotonic mediums
  • hormone prolactin plays a role in minimizing Na+ loss when salinity drops
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20
Q

what are diadromous fish and the types

A
  • spend part of their life cycle in FW and part in SW
  • catadromous: live primarily in FW but migrate to SW to breed
  • anadromous: migrate from SW to breed in FW
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21
Q

how do catadromous species regulate

A
  • hormone cortisol upregulates mechanisms that allow adults to survive in a hypertonic environment
  • increase in gill chloride cell density, size, and Na+K+ATPase activity
  • enhanced capacity to take up ions across the gut to allow water uptake
  • increased permeability of the urinary bladder for water retention
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22
Q

how do anadromous species regulate

A
  • adult salmon get a decrease in Na+K+ATPase activity and a change in isoform from alpha1a to alpha1b
  • young salmon must return to the sea and transform from a parr to a smolt
  • hormones in smoltification process: thyroxine, cortisol, growth hormone
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23
Q

gill functions

A
  • ionic regulation
  • pH regulation
  • nitrogen excretion
  • gas exchange
  • in most fish nitrogen excreted in form of ammonia
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24
Q

how is nitrogen excreted across the gills

A
  • form of ammonia as a consequence of protein metabolism
  • rapidly diffuses because cell membranes in gills are permeable to ammonia gas
  • to maintain gradient for diffusion NH3 is protonated to form NH4+
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25
Q

how is the vertebrate nervous system divided

A
  • central nervous system: brain and spinal cord
  • peripheral nervous system: afferent/sensory nerve tracts, motor/efferent nerve tracts, autonomic nervous system
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26
Q

three regions of the brain

A
  • prosencephalon (forebrain)
  • mesencephalon (midbrain)
  • rhombencephalon (hindbrain)
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27
Q

3 main parts of prosencephalon

A
  • olfactory bulbs
  • olfactory lobes (telencephalon)
  • diencephalon
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28
Q

olfactory bulbs

A

primary olfactory centres

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29
Q

olfactory lobes

A
  • integrate/process olfactory information
  • cerebrum: decision making
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30
Q

diencephalon regions

A
  • epithalamus
  • thalamus
  • hypothalamus
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31
Q

epithalamus

A
  • has nervous connections with the pineal gland
  • receives sensory inputs from the olfactory region and telencephalon
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32
Q

hypothalamus

A
  • major integratory system of the brain
  • controls pituitary function
  • major link between nervous and endocrine systems
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33
Q

optic lobe (tectum)

A
  • centre for the integration of visual inputs and other sensory information
  • memory/learning
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34
Q

cerebellum

A
  • integrates sensory information and coordinates
  • posture, swimming/movements, balance
  • most variable brain region
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35
Q

medulla oblongata

A
  • contains nerve fibres from all regions of the cns
  • receives sensory inputs/transmits efferent motor impulses
  • closely associated with nerves carrying info to and from skin, lateral line, gustary system, and viscera
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36
Q

PNS cranial nerves

A

0 - terminal
I - olfactory
II - optic
III - oculomotor
IV - trochlear
VI - abducens
V - trigemial
VII - facial
VIII - auditory
IX - glossopharyngeal
X - vagus

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37
Q

types of facial nerves

A
  • superficial
  • ophthalmic
  • deep
  • maxillary
  • mandibular
  • hyomandibular
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38
Q

0) terminal nerve fibre type

A

sensory

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39
Q

I) olfactory nerve fibre type

A

sensory

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40
Q

II) optic nerve fibre type

A

sensory

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41
Q

III) oculomotor nerve fibre type

A

sensory and motor

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42
Q

IV) trochlear nerve fibre type

A

sensory and motor

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43
Q

VI) abducens nerve fibre type

A

sensory and motor

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44
Q

V) trigeminal nerve fibre type

A

sensory

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45
Q

VII) facial nerve fibre type

A

sensory and motor

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46
Q

VIII) auditory nerve fibre type

A

sensory

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47
Q

IX) glossopharyngeal nerve fibre type

A

sensory and motor

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48
Q

X) vagus nerve fibre type

A

sensory and motor

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49
Q

spinal cord

A
  • continuous with the medulla oblangata
  • extends down the vertebral column
  • has a central canal with grey matter composed of unmyelinated nerve fibres
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50
Q

where do paired spinal nerves arise from

A

grey matter along the length of the spinal cord

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51
Q

purpose of dorsal branches/roots in spinal cord

A

carry somatic and visceral afferent (sensory) fibres and some visceral efferent fibres

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52
Q

purpose of ventral branches

A
  • carry somatic (motor) nerves and visceral efferent nerve fibres contributing to the autonomic nervous system
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53
Q

what is the autonomic nervous system composed of

A
  • sympathetic and parasympathetic components
  • involved in the control of smooth muscle, heart, and certain glands
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54
Q

types of nerves in the ANS

A
  • pre-ganglionic and post-ganglionic nerves
  • final neurotransmitter released can be acetylcholine (parasympathetic) or catecholamines noradrenaline or adrenaline (sympathetic)
  • role often antagonistic
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55
Q

what are hormones

A

chemical compounds released by one tissue that travel in the blood stream before stimulating other tissues

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56
Q

what is autocrine

A

compound chemical released by a cell which influences that cell’s physiology

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57
Q

what is paracrine

A

compound chemical released by a cell which influences adjacent cell’s physiology

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58
Q

what is endocrine

A

compound chemical released by a cell which influences physiology of cells in other organs/tissues ie hormones

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59
Q

what is the pineal gland

A
  • located on dorsal surface of diencephalon
  • sensory function: photosensitive
  • secretes melatonin (circadian rhythm)
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60
Q

importance of melatonin

A
  • provides the link between photoperiod and hypothalamic-pituitary function and between photoperiod and seasonal gonadal development
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61
Q

what is the pituitary gland

A
  • under hypothalamus
  • controls secretory activity of other endocrine glands
  • produces hormones that stimulate target tissues
  • most complex endocrine organ
  • primary link between nervous and endocrine systems
  • controlled by hypothalamus
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62
Q

parts of the pituitary gland

A
  • neurohypophysis (Pars Nervosa)
  • adenohypophysis
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63
Q

parts of adenohypophysis

A
  • pars intermedia
  • pars distalis
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64
Q

parts of pars distralis

A
  • rostral
  • distal
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65
Q

difference between adenohypophysis and neurohypophysis

A
  • adeno: produce and release hormones when stimulated by hormones from hypothalamus
  • neuro: don’t produce its own hormones but releases ones from the hypothalamus
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66
Q

hormones released from the hypothalamus

A
  • CRH: corticotropin releasing hormone
  • AVT: arginine vasotocin
  • TRH: thyrotropin releasing hormone
  • GnRH: gonadotropin releasing hormone
  • GHRH: growth hormone releasing hormone
  • GHIH: growth hormone inhibitory hormone (somatostatin)
  • PRH: prolactin releasing hormone
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67
Q

hormones released from the neurophypophisis (pars nervosa)

A
  • MCH: melanin concentrating hormone
  • AVT: arginine vasotocin
  • isotocin (analogous to oxytocin)
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68
Q

hormones released from the adenohypophysis

A
  • ACTH: adrenocorticotropic hormone
  • TSH: thyroid stimulation hormone (thyrotopin)
  • GTH: gonadotropins I and II (FSH and LH)
  • GH: growth hormone
  • PRL: prolactin
  • SL: somatolactin
  • MSH: melanophore stimulating hormone
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69
Q

hormones released by pars distalis

A
  • ACTH: adrenocorticotropic hormone
  • TSH: thyroid stimulation hormone
  • GTH: gonadotropins I and II
  • GH: growth hormone
  • PRL: prolactin
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70
Q

hormones released by pars intermedia

A
  • SL: somatolactin
  • MSH: melanophore stimulating hormone
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71
Q

why doesn’t the pars nervosa make its own hormones

A
  • it is where nerves from the hypothalamus terminate
  • hormones isotocin, arginine vasotocin, and melanin concentrating hormone are released from hypothalamus then enter hypophyseal artery then circulation
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72
Q

purpose of isotocin

A
  • reproductive
  • renal
  • cardiovascular
  • metabolic
  • hydroosmotic
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73
Q

purpose of arginine vasotocin

A
  • salt and water balance
  • mediates renal water retention
  • promotes gill Na and Cl extrusion
  • constrictor of vascular and other smooth muscles
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74
Q

purpose of melanin concentrating hormone

A
  • concentrates melanin granules in melanophores
  • lightens body colour
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75
Q

purpose of melanophore stimulating hormone

A
  • acts on melanophores to cause pigment dispersal
  • fish gets darker
  • stimulates melanin production
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75
Q

antagonistic melanin hormones

A

melanin concentrating hormone and melanophore stimulating hormone

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76
Q

purpose of somatolactin

A
  • maturation/reproduction
  • acid-base balance
  • control of ion levels
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77
Q

how does the pars distalis release hormones

A
  • produces 6 hormones in response to release of hormones from hypothalamus
  • trigger hormones arrive mainly through portal circulation
  • most hormones have effects on other endocrine organs - only prolactin has direct effects
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77
Q

purposes of prolactin

A
  • released in response to prolactin releasing hormone from hypothalamus
  • wide range of actions such as lipid metabolism and gonadal steroidogenesis
  • main role is regulation of water and ion permeability of gills, kidney, and bladder
  • decrease in permeability of water, increase ion uptake across gills
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78
Q

anatagonistic hormones regarding ion regulation

A

prolactin and arginine vasotocin

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78
Q

hormones that work together to regulate Ca

A

prolactin and somatolactin

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79
Q

thyroid

A

a diffuse gland scattered around blood vessels in the region ventral to the pharynx

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79
Q

functional unit of the thyroid gland

A
  • follicle
  • single layer of epithelial cells that enclose a fluid filled space (colloid)
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80
Q

what do thyroid cells do

A
  • take up iodide and synthesize T3 (tri-iodothyrosine) and T4 (thyroxine) from amino acid tyrosine
  • T4 prominent hormone produced
  • both stored prior to release
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81
Q

how are T3 and T4 released

A
  • released in colloid bound to glycoprotein thyroglobulin
  • secretion and release controlled by TSH (thyrotropin) which is controlled by TRH from the hypothalamus
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82
Q

T4 and T3 function

A
  • T4 is main hormone in circulation
  • T4 converted to active form (T3) in peripheral tissues
  • growth and development
  • metamorphosis
  • osmoregulation
  • metabolism?
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83
Q

where are interrenal cells located

A

in the head kidney in close association with veins

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84
Q

main hormones produced by interrenal cells

A
  • teleosts: cortisol, some cortisone and corticosterone
  • elasmobranchs: 1alpha-hydroxycorticosterone
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85
Q

how does production of cortisol work

A
  • not stored
  • synthesized when interrenal cells are stimulated by ACTH which is controlled by CRH
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86
Q

characteristics of cortisol

A
  • member of the steroid family
  • synthesized from cholesterol
  • released in response to stress
  • primary effects mediated by changes in gene expression
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87
Q

purposes of cortisol

A
  • mineralocorticoid (Na/Cl regulation, chloride cell proliferation)
  • mobilization of energy stores (glucose, FFA, protein)
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88
Q

consequences of cortisol

A
  • immunosuppression
  • decreased growth
  • impaired reproduction
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89
Q

where are catecholamines produced

A
  • chomaffin tissue
  • located in head kidney
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90
Q

what are catecholamines

A
  • adrenaline and noradrenaline synthesized from the amino acid tyrosine
  • stored prior to release
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91
Q

purpose of catecholamines

A
  • fight or flight response
  • released directly into circulation in response to cholinergic parasympathetic nervous stimulation
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92
Q

how do catecholamines work

A
  • bind to receptors on cell surface
  • mediate short-term effects aimed at increasing circulating energy substrates and blood oxygen delivery
  • rapidly cleared from blood due to costs
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93
Q

effects of catecholamines

A
  • increased ventilation and gill perfusion
  • stimulation of Na/H exchange on red blood cells
  • release of erthyrocytes from spleen
  • increased heart rate and strength of contraction
  • increase Ca entry
  • increase in blood pressure, vasoconstriction
  • release of glucose and fatty acids, increases energy substrates
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94
Q

what is the caudal neurosecretory system

A
  • exclusive to fish
  • located in posterior segment of spinal cord
  • composed of enlarged neurosecretory cells (Dahlgren cells) that originate in the spinal cord and have swollen nerve terminals that terminate in the urophysis
  • urophysis composed of axons and nerve terminal of Dahlgren cells and a network of blood vessels that receive hormones produced
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95
Q

peptide hormones produced in caudal neurosecretory system

A
  • urotensin I
  • urotensin II
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96
Q

purpose of urotensin I

A
  • involved in stress responses
  • vasorelaxation
  • osmoregulation
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97
Q

purpose of urotensin II

A
  • stimulates the smooth muscle of the reproductive tracts
  • Na exchange
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98
Q

main hormones involved in calcium homeostasis

A
  • stanniocalcin
  • calcitonin
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99
Q

properties of stanniocalcin

A
  • glycopeptide
  • produced in corpuscles of stannius (spherical bodies on or in kidney)
  • inhibits active uptake of calcium across gills
  • inhibits intestinal calcium absorption and promotes accumulation of Ca in bones and scales
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100
Q

properties of calcitonin

A
  • peptide
  • produced by ultimobranchial gland (ventral to esophagus)
  • minor regulator of Ca levels
  • inhibits gill Ca influx
    stimulates osteoblast development (bone growth)
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101
Q

properties of stanniocalcin and calcitonin

A
  • hypocalcaemic
  • antagonistic to effects of prolactin and somatolactin
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102
Q

how is fish blood volume controlled

A
  • renin-angiotensin system
  • natriurectic peptides
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103
Q

what is the renin-angiotensin system

A
  • activated by hypotension, hypovolemia, and osmotic pertubations
  • involved in maintenance of ion and fluid balance
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104
Q

renin-angiotensin system hormones

A
  • angiotensinogen
  • renin (enzyme)
  • ACE (angiotensin converting enzyme
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105
Q

where is angiotensinogen produced

A

liver

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106
Q

where is renin produced

A
  • kidney tissue
  • corpuscles of stannius
  • rectal gland of elasmobranchs
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107
Q

where is ACE (angiotension converting enzyme) produced

A
  • gill
  • kidney
  • number of other tissues
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108
Q

renin-angiotensin system process

A
  • angiotensinogen produced in liver
  • renin converts angiotensinogen to angiotensin I
  • ACE converts angiotensin I to angiotensin II
  • angiotensinase deactivates angiotensin II to angiotensin III
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109
Q

actions of angiotensin II

A
  • increase in blood pressure
  • increase in drinking
  • changes in renal function
  • overall increase in blood volume
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110
Q

what are natriurectic peptides antagonistic to

A

angiotensin II

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111
Q

what are the natriurectic peptides

A
  • ANP
  • CNP
  • VNP
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112
Q

where are natriurectic peptides produced

A

chambers of the heart in response to stretch

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113
Q

effects of natriurectic peptides

A
  • decreased drinking and drinking-coupled salt uptake by gut
  • increase extrusion of excess salt at gills and rectal gland
  • relaxation of smooth muscle, decrease in blood pressure
  • overall decrease in blood volume
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114
Q

pancreas

A
  • exocrine and endocrine
  • in some fish large lumps of endocrine pancreatic tissue (brockman bodies) are present
  • in other species endocrine pancreas is more diffuse and scattered around the gall bladder, pyloric caecae, and foregut
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115
Q

hormones produced by pancreas

A
  • all peptides
  • insulin
  • glucagon
  • somatostatin
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116
Q

properties of insulin

A
  • produced by B cells
  • promotes glucose uptake by tissues
  • gluconeogenesis
  • fatty acid uptake by liver and lipogenesis
  • anabolic - building
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117
Q

properties of glucagon

A
  • produced by A cells
  • largely oppose insulin actions
  • glycogenolysis
  • lipolysis
  • catabolic - breaking down
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118
Q

properties of somatostatin

A
  • produced by D cells
  • inhibits release of glucagon and insulin
  • promotes lipolysis and hyperglycemia
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119
Q

which pancreas hormones are antagonistic

A

insulin and glucagon, somatostatin and insulin

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120
Q

purpose of polypeptides released from the gut

A
  • control digestive processes
  • enzyme secretion
  • GI motility
  • appetite control
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121
Q

hormones released by the gut

A
  • ghrelin
  • secretin
  • gastrin
  • CCK
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122
Q

properties of ghrelin

A
  • produced by stomach
  • stimulates GH release
  • stimulates appetite
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123
Q

properties of secretin

A
  • secreted by stomach
  • stimulates pancreatic HCO3 secretion into intestine –> raises pH of intestines to receive acidic food
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124
Q

properties of gastrin

A
  • synthesized by stomach epithelium
  • stimulates gastric gland secretions and gastric motility
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125
Q

properties of CCK

A
  • synthesized by intestinal epithelium
  • stimulates pancreatic enzyme secretion and gall bladder contraction (lipid digestion)
  • decreases appetite
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126
Q

why is growth well studied

A
  • good indicator of the health of individuals and populations
  • needed metric in aquaculture and fisheries modelling/management
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127
Q

growth characteristics

A
  • net result of anabolic and catabolic processes occurring in an organism over time
  • determinate in mammals and birds
  • indeterminate in most fish
  • fish growth determined by genetic potential
  • doesnt happen at a constant rate
  • a change in length, or mass, over time
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128
Q

common equation for calculating growth

A

SGR (%BM/day) = 100(ln final mass - ln initial mass) / days

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129
Q

von bertalanaffy equation

A

Lt = Lmax (1-e^kt)
- Lt = length at point in time
- Lmax = max length attained by a species
- e = base of natural logarithms
- t = point in time
- k = growth rate coefficient

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130
Q

methods to determine growth rates/age

A
  • mark/recapture
  • back calculation from rings on hard structures
131
Q

how is growth calculated from rings on hard structures

A

deposition of minerals as fish grows leaves growth rings

132
Q

structures used to calculate growth

A
  • scales
  • otoliths
  • spines
  • vertebrae
133
Q

how are scales used to determine growth

A
  • fibroblast cells in the fibrillar plate region deposit collagen (protein) and CaCO3 (calcification)
  • circuli
  • due to faster growth in summer than winter circuli become closer to each other during winter forming an annulus
  • age determined by counting annuli
134
Q

what are circuli

A

growth ridges on scales that form at a constant rate

135
Q

what is an annulus

A

cluster of dense circuli on scales

136
Q

how is age determined in cartilaginous fish

A
  • centrum of vertebrae in some sharks
  • spines (dorsal or pectoral fin) can be used
137
Q

how are otoliths used for aging

A
  • small bones located in inner ear of bony fishes
  • can be sectioned/polished
138
Q

methods to determine instantaneous growth rates

A
  • RNA:DNA ratio
  • phenylalanine flooding dose method
139
Q

what is RNA:DNA ratio

A
  • determines instantaneous growth rate
  • dna content is constant but rna content is a function of a fish’s protein synthesis rate
140
Q

what is phenylalanine flooding dose method

A
  • determines instantaneous growth rate
  • inject fish with an excess of the 3H-phenylalanine and measure the incorporation of this radiolabel into muscle, other tissues, etc
141
Q

what is growth rate dependent on

A
  • fish’s energetic budget
142
Q

growth rate based on energetic budget equation

A

Gs + Gr = C - [(Mr + Ma + SDA) + (F + U)]
- C = rate of energy consumption
- Mr = standard metabolic rate
- Ma = metabolic rate increase due to activity
- SDA = metabolic rate increase due to specific dynamic action
- F + U = waste losses due to feces and urine rates
- Gs = somatic growth rate due to protein synthesis and lipid deposition
- Gr = growth rate due to gonad synthesis

143
Q

other factos that affect growth rate

A
  • temperature
  • hypoxia
  • photoperiod/season
  • compensatory growth
144
Q

what is compensatory growth

A

a phase of accelerated growth when favourable conditions are restored

145
Q

hormones that regulate growth

A
  • IGF-1: insulin-like growth factor 1
  • GH: growth hormone
  • GHRH: growth hormone releasing hormone
  • GHIH: growth hormone inhibitory hormone (somatostatin)
146
Q

what is myostatin

A
  • polypeptide produced primarily by skeletal muscle cells that circulates in the blood and inhibits muscle growth
  • ensures muscles do not get too large
147
Q

how is growth regulated in the hypothalamic-pituitary-growth axis

A
  • environmental stimuli, stress, and endogenous rhythms stimulate cns
  • cns releases neurotransmitters to hypothalamus
  • hypothalamus releases GHRH
  • GHRH triggers release of GH from pituitary
  • GH triggers IGF-1 to release to target tissues
  • buildup of IGF-1 and GH detected by liver makes negative feedback loop to release somatostatin and slow growth
148
Q

5 distinct periods of fish life history

A
  • embryonic period
  • larval period
  • juvenile period
  • adult period
  • senescence
149
Q

what is the embryonic period

A
  • developing fish dependent on nutrition from the mother
  • yolk, placenta connection, maternal secretions
150
Q

what is the larval period

A
  • begins with ability to capture food
  • ends with development of axial skeleton, fins, and organ systems
151
Q

what is the juvenile period

A
  • begins when fins and organ systems are fully formed
  • change from larvae to juvenile may be metamorphosis
152
Q

what is the adult period

A
  • begins when fish is reproductively mature
153
Q

what is senescence

A
  • period when growth has mostly stopped
  • gonads are degenerate and incapable of producing gametes
154
Q

phases of the embryonic period

A
  • fertilization
  • cleavage - egg phase
  • embryo phase
  • free embryo
155
Q

what happens during fertilization

A
  • sperm penetrates the egg
  • chorion stiffens due to process called water hardening
  • protects fragile embryo
156
Q

what happens in cleavage-egg phase

A
  • 1st cell until appearance of neural plate
157
Q

what happens in embryo phase

A

major organs appear until hatching

158
Q

what happens in free embryo phase

A

starts with hatching and ends when all yolk is absorbed and fish starts feeding

159
Q

types of eggs

A
  • pelagic
  • benthic
  • glutinous
160
Q

what are pelagic eggs

A
  • neutrally buoyant due to oil globulet
  • develop in the water column
161
Q

what are benthic eggs

A

laid by the female on the bottom

162
Q

what are glutinous eggs

A

attached to hard substrates on/attached to the bottom

163
Q

characteristics of the larval period

A
  • begins at exogenous feeding, ends when formation of skeleton and organs are complete and median fin fold is gone
  • typically transparent
  • some have spines for protection
  • eyes may be oddly shaped or on stalks
  • many aid in buoyancy through high surface area, oil globules, watery tissues
  • predation is heavy
164
Q

what is direct development

A
  • at the start of exogenous feeding the fish is a miniature version of the adult
  • no larval stage
  • ex. sculpins
165
Q

characteristics of the juvenile period

A
  • begins when organ systems and fins fully formed
  • ends when sexually mature
  • miniature adult
  • rapid growth period
166
Q

types of feeding habits

A
  • detritivore
  • herbivore
  • carnivore
  • omnivore
167
Q

detritivore

A

consume freshly dead or partially decomposed organ material

168
Q

herbivore

A

eat plant-based material

169
Q

carnivore

A

feeding on other animals

170
Q

types of carnivores

A
  • macrocarnivores
  • microcarnivores
  • parasites
171
Q

macrocarnivores

A

piscovorous fish and those that feed on crustaceans

172
Q

microcarnivores

A

feed on zooplankton, fish eggs

173
Q

parasites

A

feed on other fish without killing them

174
Q

omnivore

A

consume a variety of food types, usually opportunistic

175
Q

types of fish diets

A
  • europhagous: mixed diet
  • stenophagous: limited number of food sources
  • monophagous: only one food source
176
Q

types of prey capture methods

A
  • oral manipulators
  • ram feeders
  • suction feeders
177
Q

oral manipulator feeders

A
  • use teeth to eat
  • scraping, biting, gripping, grasping
178
Q

ram feeders

A
  • take food with open mouth ramming food through mouth
  • continuous swimmers that strain food
179
Q

suction feeders

A
  • fish is stationary and creates inward directed water current by expansion of buccal cavity
  • often combined with protrusible jaws
180
Q

types of mouth structures

A
  • ancestral (plesiomorphic)
  • advanced (apomorphic)
181
Q

ancestral (plesiomorphic) mouth structure

A
  • firm jaws and sharp teeth
  • immobile premaxilla and mobile maxilla
182
Q

advanced (apomorphic) jaw type

A
  • mobile premaxilla and mobile maxilla
  • premaxilla can swing ventrally and protrude
183
Q

advantages of advanced jaw type

A
  • large gape relative to jaw size
  • suction volume increased
184
Q

why can sharks protrude their jaws

A

upper jaw not fused to cranium

185
Q

where are teeth located in fish

A
  • on jaws
  • on lower part of mouth
  • on tongue
  • on palate
  • pharyngeal teeth
186
Q

8 types of teeth

A
  • canine
  • villiform
  • molariform
  • cardiform
  • incisor
  • fused into beaks
  • flattened triangular cutting teeth
  • pharyngeal teeth
187
Q

canine teeth

A

conical teeth found at the corners of the mouth

188
Q

villiform teeth

A

generally small fine teeth but can become elongate

189
Q

molariform teeth

A

pavement-like cursing teeth, can be individual or form plates

190
Q

cardiform teeth

A

very fine pointed teeth

191
Q

incisor teeth

A

large teeth with flattened cutting surfaces for feeding on molluscs and crustaceans

192
Q

beak teeth

A

used for scraping algaae off corals

193
Q

flatted triangular cutting teeth

A

often serrated to aid in cutting action

194
Q

pharyngeal teeth

A

assist in holding prey and in many species have structural modifications for crushing, grinding, tearing

195
Q

what are gill rakers

A

inwardly directed bony or cartilaginous projections from gills

196
Q

gill rakers in piscivores

A
  • short and stubby
  • prevent prey from escaping
  • descale prey
  • protect gill filaments
197
Q

gill rakers in filter feeders

A
  • long and thin
  • closely spaced
  • paddlefish, basking shark
198
Q

basking shark gill rakers

A

shed every autumn and regrow in spring

199
Q

palatal organ (pharyngeal pad)

A
  • thick muscular pad on roof of pharynx in cyprinids
  • involved in the selective retention of food particles inside the oropharyngeal cavity
200
Q

epibranchial organ

A
  • a paired dorsal diverticulum at the posterior limit of the pharynx in certain microphagous fishes
  • in all forms prominent gill rakers extend into the organ
  • small food particles get trapped
201
Q

differences in digestive tract morphology depending on diet

A
  • structure of mouth and teeth, gill rakers, pharynx, stomach, and length of intestine
  • carnivorous fish: definite stomach (foregut)
  • herbivorous fish: no stomach, extended midgut area
202
Q

relative gut length

A
  • relative gut length RGL = gut / body length
  • high RGL = species consuming detritus, algae
203
Q

stomach characteristics

A
  • produces hydrochloric acid
  • when stomach distends parasympathetic nervous stimulation of gastric glands which produce HCl and pepsinogen
  • low pH converts inactive pepsinogen to active pepsin
  • other enzymes secreted work on lipids, carbohydrates, and chitin
  • if no stomach HCl or pepsin is formed in the gut
204
Q

which cells produce HCl

A

parietal cells

205
Q

which cells produce pepsinogen

A

chief cells

206
Q

where is bile produced

A

liver

207
Q

pancreas characteristics

A
  • produces HCO3 which raises gut pH
  • produces many digestive enzymes stored in inactive forms (zymogens)
208
Q

process when food enters pancreas

A
  • food in the gut
  • activation
  • proteases produced by intestine
  • converts trypsinogen into trypsin
  • activates pancreas enzymes
209
Q

zymogens made by the pancreas

A
  • proteases: protein breakdown
  • amylases: starch breakdown
  • chitinases: chitin breakdown
  • lipases/co-lipases/phospholipases: lipid breakdown
210
Q

gall bladder

A
  • stores bile
  • emulsification to allow digestion by lipases and esterases
  • neutralizes HCl from stomach
  • maintains alkalinity of the gut pH
211
Q

intestine

A
  • surface epithelial cells can produce a variety on enzymes that act on carbs and peptides
212
Q

enzymes produced by intestine epithelial cells to act on carbs

A
  • B = insulin
  • A = glucagon
  • D = somatolactin
213
Q

what is specific dynamic action

A

increase in metabolic rate following the ingestion of a meal

214
Q

specific dynamic action

A
  • integrates the sum of all energy expenditures involved in feeding
  • includes a muscular mechanical component and the endogenous post-absorption of nutrients and digestion
215
Q

why is there a major influence on oxygen consumption with specific dynamic action

A
  • energy requirements of biochemical transformation of food
  • protein synthesis occurring in post-absorptive stage
216
Q

how does oxygen consumption change during specific dynamic action

A
  • immediate spike in O2 consumption rate then slowly returns to normal
  • spike smaller and return to baseline faster for small meals
  • when in a hypoxic environment initial spike is smaller but it takes longer to return to baseline
217
Q

main fish mating systems

A
  • semelparity
  • iteroparity
  • promiscuous reproduction (broadcast spawning)
  • polygamy
  • polygyny
  • polyandry
  • monogamy
218
Q

semelparity

A

only reproduce once

219
Q

iteroparity

A

individuals spawn two to several times in their life

220
Q

promiscuous reproduction (broadcast spawning)

A
  • no obvious mate choice occurs
  • large groups/multiple partners
  • big mating aggregations
221
Q

polygamy

A

one sex has multiple partners

222
Q

polygyny

A

a few males get multiple female mates

223
Q

polyandry

A

one female mates with several males

224
Q

monogamy

A

fish live in pairs and stay together and mate

225
Q

alternative reproductive strategies

A
  • sneaking in
  • hermaphrodites
  • all female reproduction
226
Q

sneaking reproductive strategies

A
  • jack males: small precocious males that sneak in to breed with females
  • satellite males: resemble females and sneak in to fertilize eggs
227
Q

forms of hermaphroditism

A
  • synchronous
  • sequential (protandrous and protogynous)
228
Q

synchronous hermaphroditism

A
  • capable of releasing viable eggs and sperm in the same spawning
  • least common
  • when there are limited opportunities or time for spawning
229
Q

sequential hermaphroditism

A
  • change sex over their life history
  • protandrous: males first then change to females
  • protogynous: females first
230
Q

types of all female reproduction

A
  • gynogenetic females (parthogenesis)
  • hybridogenetic females
231
Q

gynogenetic females

A
  • females are 3N and so are eggs (no meiosis)
  • sperm from males not required for fertilization
  • only required to activate cell division
  • only clones produced
232
Q

hybridogenetic females

A
  • diploid
  • all female haploid eggs
  • paternal genes discarded at meiosis during gamete production
  • eggs fertilized by another species by only females produced
  • male contribution lost after one generation
233
Q

types of reproductive guilds

A
  • non-guarders
  • guarders
  • bearers
234
Q

types of non-guarders

A
  • open substrate spawners
  • pelagic spawners
  • benthic spawners
  • brood hiders
235
Q

types of guarders

A
  • substrate choosers: no nest construction
  • nest spawners: cavity, plant material, bubbles
236
Q

oviparous

A

produce eggs that hatch outside the body

237
Q

types of bearers

A
  • external (still oviparous): mouth, skin, forehead brooder
  • internal (produce live young): internal fertilization, requires intromittent organ to deposit sperm
238
Q

types of internal bearers

A
  • ovoviviparous: internal growth and fertilization but no additional nourishment from mother
  • viviparous: maternal nourishment
239
Q

adpatations of viviparity

A
  • trophotaeniae
  • trophonemata
  • intrauterine cannabilism or oophagy
  • placental viviparity
240
Q

trophotaniae (goodeids)

A

fetal processes from gut or anus that increase absorbing surface and enhance absorption of nutrients from ovary

241
Q

trophonemata (rays)

A
  • tufts of uterine epithelium that enter embryo through spiracle and pass into esophagus
  • nutrients secreted enter gut of embryos
242
Q

placental viviparity (requiem sharks and hammerhead sharks)

A
  • yolk sac placenta
  • temporary association with maternal tissue
  • appendiculae: vascular ridges that develop on yolk stalk and take up uterine milk
243
Q

sexual dimorphism traits

A
  • size
  • breeding tubercles/contact organs
  • intromittent organs
  • dichromatism (colour differences)
  • some differences only at spawning
244
Q

fish testes

A
  • usually paired and suspended in anterior body cavity by mesentaries called mesorchia
  • smooth, white, up to 12% of BW
245
Q

male reproductive organs in chondrichthyes

A
  • sperm travel through tubules before being released into urogenital sinus or stored in sperm sac
  • sperm delivered to female through groove in claspers
  • Leydig’s gland: modified cells in the anterior kidney that secrete seminal fluid into the epididymus
246
Q

male reproductive organs in teleosts

A
  • in most groups no connection between reproductive and urinary systems
  • sperm move down sperm ducts and exit through a genital pore
  • in some species sperm and urine enter into a common urogenital sinus
  • in some species sperm are released into the body cavity and exit through a genital pore
247
Q

fish ovaries

A
  • suspended by mesovarium
  • usually paired
  • large yellow organs, 30-70% BW
248
Q

female reproductive organs in chondrichthyes

A
  • eggs released into body cavity (gymnovarian condition)
  • enter the oviducts through a funnel (ostium) located anterior to the ovaries
  • reach shell gland where fertilization occurs
  • horny shell (oviparous) or membrane (viviparous) is secreted
  • posterior portion of oviduct can be enlarged to serve as a uterus
249
Q

female reproductive organs in non-teleost osteichthyes

A
  • gymnovarian condition
  • eggs released into body cavity
  • enter oviduct through funnel
250
Q

female reproductive organs in teleosts

A
  • oviducts continuous with outer tissue layers of the ovaries (cystovarian condition)
  • eggs exit through genital pore located between anus and urinary pore
251
Q

factors that control reproduction

A
  • photoperiod
  • temperature
  • hypothalamic-pituitary-gonad axis
252
Q

brain/hypothalamus control of reproduction

A

GnRH gonadotropin releasing hormone

253
Q

pituitary gland control of reproduction

A
  • gonadotropins: GtH (FSH and LH)
  • stimulate gonadal development and secretion of steroids
254
Q

gonad control of reproduction

A

gonadal steroid hormones

255
Q

gonadal steroid hormones

A
  • estrogen/estrodiol: stimulates production of vitellogenin
  • progestin: stimulated by LH - oocyte maturation
  • androgens: secondary sexual characters, behaviour
256
Q

where are sperm produced

A
  • seminiferous tubules in bony fish
  • spermatic ampullae (cavities) in sharks and agnathans
257
Q

how do sperm cells develop

A
  • develop in association with Sertoli cells whose function is stimulated by FSH (follicle stimulating hormone)
  • Leydig cells produce androgenic steroid hormones after being stimulated by leutenizing hormone (LH)
258
Q

steps of sperm production

A
  • spermatogonium (2n) undergoes mitoses to become spermatocytes (2n)
  • spermatocytes undergo meioses to become spermatids (1n)
  • spermatids undergo differentiation to become spermatozoans (1n)
259
Q

oogenesis

A

the process by which primordial germ cells produce oocytes that become ready to be fertilized eggs

260
Q

6 stages of oocyte development

A
  • oogonia proliferation
  • chromatin nucleolus stage
  • primary growth
  • secondary growth
  • oocyte maturation
  • ovulation
261
Q

oogonia proliferation stage

A
  • stem cells in the germinal epithelium undergo mitoic division
  • frequently form nest cells
  • oogonia are surrounded by pre-follicle cells
262
Q

chromatin nucleolus stage

A
  • meiosis I starts
  • follicle still not completely formed
  • nucleoli can be seen on periphery of the nucleus
  • process of meiosis arrested prior to completion
  • oocyte still within germinal epithelium
263
Q

primary growth stage of oocyte development

A
  • oocyte covered by a full layer of follicular cells
  • has one to many nucleoli (PGon and PGpn)
  • oocyte contains balbiani bodies, cortical alveoli (food for embryo), and oil droplets
  • zona pellucida develops between ooxyte and follicular cells
264
Q

secondary growth stage (vitellogenesis)

A
  • stimulated by estrogen
  • uptake of vitellogenin (complex glycophospholipoprotein produced by liver) by the oocyte
  • vitellogenin transformed into lipoprotein and protein yolk stored in yolk globules
  • further accumulation of oil droplets
  • oocyte increases dramatically in size
265
Q

oocyte maturation

A
  • morphological and physiological changes to oocyte
  • nucleus takes an eccentric position, migrates to periphery and breaks down - first meiotic division is completed
  • egg gets bigger due to hydration of egg
  • oil droplets fuse to become oil globules and eventually form one oil globule in marine eggs
  • meiosis I is completed
  • cells arrest at metaphase of 2nd meiotic division
266
Q

ovulation

A
  • shared basement membrane, follicle cells, and overlying germinal epithelium break
  • creates opening through which oocyte moves into ovary lumen
  • post-ovulatory follicle complex is left
267
Q

what happens in ovulation doesn’t occur

A
  • oocytes undergo atresia
  • process of degeneration and removal of oocytes from the ovary
  • nutrients may be reabsorbed
268
Q

differences in fish eyes compared to mammals

A
  • lens is round and cannot change shape
  • eyes generally positioned laterally but protrudes and eyes bulge
  • very few fish with eyelids but have other structures to protect the eye
  • pupil is usually round or elliptical and can’t change size
  • many structural adaptations
  • some fish have vestigial eyes
269
Q

how fish lens work

A
  • generally round and cannot change shape
  • some elasmobranchs have elliptical lens
  • focus achieved by moving position of lens not changing shape
  • very high refractive index = light bending ability
270
Q

fish eye position

A
  • laterally (side of head)
  • lens protrudes through pupilar opening in the iris
  • eye bulges from the body
  • large field of view to almost behind animal
  • binocular vision in front
271
Q

protective eye structures

A
  • cornea has 4 layers to protect the lens
  • spectacle for fish that live on sandy/silty bottoms
  • sharks have nictitating membrane and roll eye into sockets
  • some rays have eye-flap pupillary operculum - not protective but increases sensitivity to movement in the visual field
272
Q

fish pupil

A
  • mostly round or elliptical
  • fixed (cannot change size)
  • in many elasmobranchs it can be a slit or crescent shape and can change in size
273
Q

eye structural adaptations

A
  • positioned forward
  • directed upward
  • on short stalks
  • divided into aerial and aquatic vision
274
Q

parts of the anterior eye

A
  • cornea
  • iris
  • lens
275
Q

cornea

A
  • made of 4 tissue layers and normally clear
  • can have some patches of changeable colouration to eliminate short wavelength light
  • sclera clear in area of cornea
276
Q

sclera

A
  • aka sclerotic coat
  • tough connective tissue layer that goes around the entire eye
  • can be strengthened by scleral ossicles or cartilage
277
Q

iris

A
  • elipsoid in most fish
  • usually incapable of movement for light regulation
  • some have contractile irises
  • pupil: gap in the iris
278
Q

lens

A
  • generally round and cannot change shape
  • composed of 50% protein and usually clear but can have some colour
  • muscle attached to bottom of eye moves lens to focus
279
Q

how do fish focus eyes

A
  • muscle attached to bottom layer of eye contracts/relaxes
  • moves lens closer or further away from retina
280
Q

difference in teleost and elasmobranch focusing

A
  • teleosts: retractor muscle pulls lens inward towards retina
  • elsamobranchs: protractor muscle pulls lens outward
281
Q

parts of the posterior eye

A
  • sclera
  • argentea (stratum argenteum)
  • choroid
  • tapetum lucidum
  • retina
282
Q

argentea (stratum argenteum)

A
  • stops light from entering the eye through its walls
  • important for fish with transluscent tissues around eye
283
Q

choroid

A
  • highly vascularized region between sclera and retina
  • supplies blood to retina (highly metabolic tissue)
  • enhances visual sensitivity under low light conditions
  • expanded in back of eye to form choroid body or gland associated with a rete mirable since metabolically active eye needs blood with a lot of ATP
284
Q

tapetum lucidum

A
  • highly reflective layer of choroid or retina
  • guanine crystals reflect light that has passed through visual cells back to system
  • adaptation for dim light conditions
  • pigment cells can migrate forward to reduce reflectivity
285
Q

retina

A
  • light sensitive part of the eye
  • photoreceptors that contain pigments that absorb light (rods and cones)
  • functions over range of light intensity
  • accommodation to light intensity by structural changes
  • pigmental absorption of light stimulates rods/cones to send electrical impulses to the optic nerve
286
Q

rods vs cones

A
  • rods: only detect light intensity, black and white vision, low light
  • cones: bright light, colour vision, three types with different colour reception
287
Q

structural changes in retina to accommodate light intensity

A
  • retinomotor migration of rods, cones, and melanin granules in pigment epithelium
  • takes about 30 minutes
288
Q

olfaction process

A
  • stimulation of sensory receptors in olfactory organ
  • olfactory nerve I
  • olfactory bulb
289
Q

olfactory organs

A
  • found in sacs or pits connected to external surface by nares/nostrils
  • anterior portion of head
  • usually bilateral
  • has incurrent and excurrent nares for water to flow through
  • pits/sacs lined with olfactory epithelium with olfactory receptors
  • folding of olfactory epithelium forms olfactory rosette
290
Q

olfactory epithelium

A
  • ciliated non-receptor cells, receptor cells, supporting cells, and mucous cells
  • ciliated cells move water
  • olfactory sensitivity related to area of olfactory epithelium and density of receptor cells
291
Q

olfactory receptor cells

A
  • olfactory receptor neurons
    two types: ciliated and microvillis
  • odorants bind to receptors on microvilli and cilia
  • send a slender cylindrical dendrite toward the surface of the epithelium
  • directly connected with the olfactory bulb by its axon
292
Q

taste

A

detects dilute solutions by contact mostly for food detection

293
Q

location of taste

A
  • cutaneous taste buds on exterior surfaces innervated by facial nerve VII
  • internal taste buds innervated by glossopharyngeal IX and vagus X nerve
294
Q

acusticolateralis system

A
  • senses sounds, vibrations, and other displacements of water
  • involved in hearing, equilibrium, balance, and orientation in 3d space
  • includes inner ear, swim bladder, lateral-line mechanoreceptors
295
Q

parts of the inner ear

A
  • dorsal part (pars superior)
  • ventral part (pars inferior)
296
Q

dorsal part of the ear (pars superior)

A
  • 3 semi-circular canal oriented in vertical, horizontal, and lateral planes
  • ultricus with small otolith (ear stone)
  • functions in equilibrium and balance
297
Q

ventral part of the ear (pars inferior)

A
  • sacculus
  • lagena
  • corresponding otoliths
  • sound detection/hearing
298
Q

how does equilibrium and balance work

A
  • 3 semicircular canals filled with lymph and detect changes in pitch, yaw, rotation, or acceleration
  • each SC has an ampulla with hair cells and a gelatinous cupula that partially blocks the canal
  • when fish moves in any direction endolymph moves and bends cupula which is sensed by hair cells that send nerve impulses to balance/equilibrium centre of the medulla
  • integration of info from all three ampulla allow proper motor responses of the fish
  • ultricus is believed to be main gravistatic organ in fish
299
Q

hearing structures

A

otolithic organs in pars inferior (lagena and sacculus)

300
Q

how fish hear

A
  • otoliths in gelatinous medium that separates them from sensory macula with many hair cells
  • when sound vibrations reach a fish body is moved by water but otoliths are dense and movement lags behind
  • otolith movement causes gelatinous medium to move and movement is detected by hair cells
  • each hair cell has 2 types of cilia: kinicilium and sterocilia
  • movement of sterocilia toward kinocilium increases firing of afferent nerves which is processed by brain as hearing
301
Q

how can swim bladder be used to improve hearing

A
  • gas is more compressible than water and pulsates when exposed to sound
  • can use pulsation of swim bladder wall
  • need to have a otophysic connection between swim bladder and inner ear
  • weberian ossicles: 4 small bones extending from swim bladder to skull
  • direct extensions of gas bladder to back of skull
302
Q

function of the lateral line

A
  • detect water movements around fish including velocity and direction
  • used to detect prey, school, and avoid obstacles
303
Q

morphology of lateral line

A
  • canal pores open to environment
  • neuromasts (similar to ampullae of semicircular canals) lie between canal pores
  • canal full of endolymph
  • movement of endolymph moves cupula and bends cilia of hair cells
  • movement of lymph stimulates neuromasts
304
Q

what are electroreceptors

A
  • allow fish to perceive electric and magnetic fields
  • detect difference in voltage between skin and where receptor is located
  • present in lampreys, elasmobranchs, a few teleosts
  • often concentrated in head area
  • uses: prey detection, navigation, communication
305
Q

types of electroreceptors

A
  • ampullary
  • tuberous
306
Q

ampullary electroreceptors

A
  • external pit organs
  • used in fish that use passive electroreception
  • sense low frequency stimuli
  • filled with mucopolysaccharide gel
  • ampullae of lorenzini in chondrichthyes
307
Q

tuberous electroreceptors

A
  • no opening to the exterior
  • found in lampreys and species involved in active electroreception
  • sensitive to high frequency stimuli
  • located in epidermis
  • first thought to be taste or mechanoreceptors
308
Q

electrical communication

A
  • found in knifefish and elephant-nose fish and catfish = weakly electric fish
  • some fish use electricity to stun prey - called strongly electric fish
309
Q

how does electrical communication work

A
  • electrical organ discharge produced by modified muscle cells (erythrocytes) in the tail region
  • discharge in response to stimulation from spinal motor nerve
310
Q

types of electrical communication

A
  • pulse type: short impulses separated by gaps (clickers)
  • wave type: produces continuous waveform (hummers)
311
Q

why do fish modify amplitude, frequency, pulse length, interpulse duration of electrical signals

A
  • species-specific nature of discharge
  • provides info about sex, size, maturation state, location, distance, individual identification
  • altered by hormones
312
Q

function of electrical communication

A
  • agonistic behaviour (territoriality)
  • reproductive behaviour/courtship
  • electrolocation
313
Q

how do fish communicate visually

A
  • movements of body structures
  • changes in posture
  • changes in colour
314
Q

how do fish change colour

A
  • pigments in chromatophores
  • located in dermis and sometimes epidermis
315
Q

types of pigments

A
  • melanins: dark colouration
  • carotenoids: lipid-soluble, yellow to red
  • pteridines: water-soluble, bright yellows and reds
  • phycocyanins: blue
  • purines: guanine, silvery skin
316
Q

types of colour displays

A
  • static
  • dynamic
317
Q

static colour displays

A
  • don’t change or change slowly
  • informs about species, sex, reproductive condition, danger
  • hormones important
  • sex steroids, MSH, MCH
  • changes in number of chromatophores
318
Q

dynamic colour displays

A
  • rapid change
  • exposure of coloured concealed areas
  • under nervous/hormonal control
  • noradrenaline, adrenaline, acetylcholine
319
Q

light production in deep-sea fish

A
  • bioluminescence (depends on enzyme luciferase)
  • found in photophores with and without symbiotic bacteria
320
Q

how many fish can produce sound

A

50 families

321
Q

mechanisms of sound production

A
  • stridulation
  • release of gas from swim bladder or anus
  • drumming
  • hydrodynamic production
322
Q

stridulation

A
  • grinding or rubbing together of skeletal parts
  • clicks, scratches
  • 100-8000Hz
323
Q

drumming

A
  • using muscles attached to swim bladder from skull or vertebrae or are incorporated into swim bladder wall
  • up to 1000Hz
324
Q

hydrodynamic sound production

A
  • when a fish quickly changes direction or velocity
  • restles or roars
  • low frequency
  • schooling
325
Q

purpose of sound production

A
  • reproductive behaviours: mate attraction, timing of gamete release
  • agonistic behaviours: territory defense, fighting
  • warning/release responses: startle predator
326
Q

chemical communication

A

involves release and reception of pheromones by gustation or olfaction

327
Q

pheromone

A
  • chemical substance secreted externally that influences the physiology or behaviour of other animals of the same species
  • amino acids, bile salts, nucleotides, gonadal steroids
328
Q

functions of chemical communication

A
  • reproductive cues: recognize mates/young, courtship
  • marking territory
  • alarm substances
329
Q

how do alarm substances work

A
  • H3NO
  • catfishes, characins, knifefishes
  • produced in epidermal alarm cells of head and anterior body following injury
  • sends message to schoolmates and other closely related species to take escape actions
330
Q
A