Exam 3 Flashcards
(308 cards)
1
Q
How are hormones transported throughout the body?
A
Hormones rely on capillary network (no ducts) to move throughout the body (moves in blood stream through whole body but only targets cells that have specific receptors
2
Q
Thyroid gland
A
largest endocrine gland, made mostly of thyroid follicles (protein and thyroglobulin rich sacs) secretes T3 & T4 in RESPONSE to TSH
3
Q
What are the functions of the thyroid gland?
A
in endotherms increases molecular activity of the mitochondria which leads to an increase of metabolic rate, O2 consumption, heat production (calorigenic effect), appetite, growth hormone secretion, alertness, and reflex speed
In ectotherms thyroid hormone affects body temperature, growth, molting, and gonad maturation
4
Q
what hormones are secreted by the thyroid gland?
A
Thyroid hormone: T3 (triiodothyronine) and T4 (thyroxine)
5
Q
Ultimobranchial bodies location
A
mammals: part of thyroid, form population of parafollicular (C) cells
fish, amphibians, reptiles and birds: separated paired cell masses in the throat
6
Q
Ultimobranchial bodies hormones secreted
A
CALCITONIN, lowers blood levels of calcium by extracting calcium from blood and depositing it in bones
7
Q
Ultimobranchial bodies function
A
stimulate osteoblast activity and bone formation in children
8
Q
Parathyroid glands location/anatomy
A
mammals: 4 glands in posterior of thyroid gland
other vert.: located on thyroid and dispersed along veins in neck
9
Q
Parathyroid hormones
A
secretes parathyroid hormone (PTH), works with calcitonin, kidney keeps calcium and pulls calcium from secretion
10
Q
Parathyroid hormones function
A
increases blood Ca2+ levels by promoting kidney retention
*teleosts instead regulate calcium using stomolactin from pituitary and store it in their scales
11
Q
Thymus location/anatomy
A
bilobed gland in the mediastinum superior to heart, Goes through involution (shrinking) at puberty
12
Q
Thymus hormones
A
secretes hormones (thymopoietin, thymosin, and thymulin) that stimulates development of other lymphatic organs and activity of T lymophocytes
*Site of mature T cells for immune defense
13
Q
Thymus function
A
main function is developing immune systems in babies and kids
thymus influences 3 systems: endocrine, lymphatic, and immune
14
Q
Adrenal glands mammals anatomy
A
fusion of 2 glands: Medulla (inner core) and cortex (outer core)
Medulla: smaller inner core of adrenal gland, high blood flow, from neural crest
Cortex: larger outer layer, high lipid and cholesterol concentration, from splanchnic mesoderm
15
Q
chromaffin cells
A
modified sympathetic neurons without dendrites or axons
16
Q
Adrenal glands anatomy in fish, amphibians, and amniotes
A
Fish: medulla and cortex are separate in pronephros/kidney area
Amphibians: tissues intermingle and form strands near kidneys
Amniotes: cortical cell and chromaffin cells mingle near kidney but not integrated, receive their own blood supply
17
Q
Adrenal gland hormones secreted
A
CATACHOLAMINES (epinephrine and norepinephrine) and dopamine (from chromaffin cells in medulla)
CORTICOSTEROIDS: stress hormones and sex hormones, released from the cortex (in non-mammals cortical hormones are used to regulate sodium transport and metabolism)
18
Q
Adrenal gland function
A
Fight or flight hormones (increase allertness and blood to heart and lungs, decrease digestion and urine production)
Stress and sex hormones
19
Q
Pancreatic islets anatomy
A
tetrapods: composite gland with endocrine and exocrine chunks
cyclostomes and telosts: pancreatic islet tissue found along the liver, gallbladder, and bile ducts (exocrine and endocrine separate but close)
chondrichthyans and coelacanths: islets near ducts and within the pancreas
20
Q
Pancreatic islets hormones
A
Alpha cells: secrete glucagon between meals when blood glucose concentration is falling
Beta cells: secrete insulin during and after meal when glucose and amino acid blood levels are rising
Delta cells: secrete somatostatin, which inhibits both glucagon and insulin
21
Q
Pancreatic islets function
A
Secretes hormones to regulate blood glucose levels
Glucagon: prevents drop of blood glucose
Insulin: lower blood glucose (glucose into cells)
Somatostatin: inhibits glucagon and insulin
22
Q
Hypothalamus location/anatomy
A
Shaped like a flattened funnel and forms floor and walls of third ventricle of brain
23
Q
hypothalamus relation with pituitary gland
A
pituitary gland is suspended from hypothalamus by a stalk (infundibulum), pituitary gland carries out most of the functions of the hypothalamus
24
Q
pituitary gland anatomy
A
kidney bean attached to hypothalamus by infundibulum
composed of 2 structures of independent origins
anterior pituitary (adenohypophysis)
Posterior pituitary (neurohypophysis)
25
hypothalamus function
master regulator of endocrine system
Regulates primitive functions from water balance and thermoregulation to sex drive and childbirth
(*sends directions to pituitary gland who then sends hormones to regulate the rest of the body)
26
Anterior pituitary gland location
linked to hypothalamus by hypophysial portal system (2 capillary beds before heart, hypothalmic releasing and inhibiting hormones regulate anterior pituitary secretions
27
Follicle stimulating hormone (FSH)
Anterior pituitary gland, secretion of ovarian sex hormones, development of ovarian follicles, and sperm production
28
Luteinizing hormone (LH)
anterior pituitary gland, stimulates ovulation, progesterone secretion, testosterone secretion
29
Thyroid-stimulating hormone (TSH)
anterior pituitary gland, secretion of thyroid hormone & growth of thyroid gland
30
Adrenocorticotropic hormone (ACTH)
anterior pituitary gland, stimulates adrenal cortex to secrete glucocorticoids (especially cortisol), important in stress response
31
Prolactin (PRL)
anterior pituitary gland, -stimulates mammary glands to make milk
32
Growth hormone (GH)
anterior pituitary gland, stimulates mitosis and cellular division
33
- Six different hormones are secreted by the anterior pituitary gland. Name three of these and describe their target organs and their functions.
o Prolactin (PRL): stimulates mammary glands to make milk
o Luteinizing hormone (LH): targets reproductive system, stimulates ovulation, progesterone secretion, testosterone secretion
o Thyroid stimulating hormone (TSH): secretion of thyroid hormone and growth of thyroid gland
34
posterior pituitary location/anatomy
much smaller than anterior pituitary, nerve tissue not a true gland, nerve cell bodies in hypothalamus pass down the stalk as hypothalamo-hypophysial tract, hypothalamic neurons secrete hormones that are stored in neurohypophysis (AKA posterior pituitary) until released into blood
35
Posterior pituitary hormones
Antidiuretic hormone (ADH) - increases water retention, thus reducing urine volume and preventing dehydration concentrates urine by pulling water into kidney tubules
Oxytocin (OT) - promotes feelings of emotional bonding between partners, Stimulates labor contractions during childbirth, Stimulates flow of milk during lactation, love sex and birth
36
pineal gland (epiphysis) location/anatomy
in brain, attached to roof of 3rd ventricle beneath posterior end of corpus callosum
*in many vertebrates it is located just under the skin on the top of the head (containing photoreceptors)
37
pineal gland hormones
melatonin, may also regulate other hormones and the immune systemp
38
pineal gland function
influences timing of puberty in humans (undergoes involution at 7)
plays role in circadian rhythms (synapses with optic nerve fibers)
may help regulate other hormones and the immune system
informs about seasonal rhythms for mating
39
Gastrointestinal tract hormones in amniotes vs fishes
amniotes: gastrin, secretin, cholecystokinin (CCK)
fishes: bombesis
40
gastrin
secreted by stomach, which stimulates secretion of enzymes and hydrochloric acid
41
secretin
when chyme moves to the intestines, stimulates bicarbonate release to buffer low pH (so pancreatic enzymes can be effective)
42
cholecystokinin (CCK)
activated by intestine, secreted by CCK cells Stimulate pancreas to secrete juice Stimulate gallbladder to release bile
43
bombesin
replaces gastrin and is secreted by stomach to release gastric acid
Bombesin has a wide range of effects apart from the stomach (thermoregulation, digestive motility) so replacement by gastrin allows hormones to become more specialized
44
ovaries homones
theca cells make androstenedione converted to estradiol by granulosa cells (most common form of estrogen) after ovulation the remains of the follicle become the corpus luteum and secrete progesterone
45
functions of estradiol and progesterone
Development of female reproductive system and physique including adolescent bone growth
Regulate menstrual cycle, sustain pregnancy
Prepare mammary glands for lactation
46
Intersitial cells
cells nestled between seminiferous tubules, release testosterone and other steroids
47
testosterone
Stimulates development of male reproductive system in fetus and adolescent, and sex drive
Sustains sperm production
48
Evolutionary trends in the endocrine system across vertebrates
Endocrine organs often more dispersed/less compacted in fishes and amphibians than in amniotes:
Adrenal glands – adrenocortical tissue and chromaffin
cells go on to form cortex and medulla in amniotes
Incorporation of parafollicular cells into thyroid gland
Pancreatic islet cells within pancreas
Functions of hormones differ across vertebrate groups:
Prolactin stimulates milk production in mammals
but promotes growth and pigment development in
reptiles and amphibians
New hormones replace function of old ones in some systems:
Example: gastrin replaces bombesin and CCK in
stomach in birds and mammals; CCK moves to
intestine
49
CNS components and terminology
central nervous system containing brain and spinal cord
a collection of nerve fibers traveling together is a tract in CNS
a collection of nerve cell bodies is a nucleus in CNS
50
PNS components and terminology (PNS)
PNS is broken into sensory division (containing visceral sensory division and somatic sensory division) and motor division (containing somatic motor division and Visceral motor division (made of sympathetic and parasympathetic divisions) )
a collection of nerve fibers traveling together is a nerve in PNS
a collection of nerve cell bodies is a ganglion in PNS
51
visceral sensory
*return signals from body organs, blood vessels, airways
division of PNS, monitor the internal environment and organ systems.
52
visceral motor
*sends signals to visceral muscles in gut, heart, exocrine glands, ect.
division of PNS, controls involuntary functions mediated by the activity of smooth muscle fibers, cardiac muscle fibers, and glands.
53
somatic sensory
*returns signals from external stimuli (olfactory, mechanical, thermal)
division of PNS, conscious perception of touch, pressure, pain, temperature, position, movement, and vibration
has two major components: a subsystem for the detection of mechanical stimuli (e.g., light touch, vibration, pressure, and cutaneous tension), and a subsystem for the detection of painful stimuli and temperature.
54
somatic motor
*sends signals out to govern locomotor response
division of PNS, allows you to move and control muscles throughout your body. It also feeds information from four of your senses — smell, sound, taste and touch — into your brain
55
Receptors vs effectors
The nervous system RECIEVES information from one or more receptors
the nervous system TRANSMITS information to one or more effectors, can be mechanical (muscles) or chemical (glands)
56
Neuroglia (nerve +glue)
microglia, oligodendrocytes, schwann cells, ependymal cells, astrocytes, satellite cells
*glial cells do not transmit impulses and instead support , nourish, insulate neurons and bind together nervous tissue
57
microglia
macrophages that clean debris, CNS
57
oligodendrocytes
cells insulate axons, CNS
57
schwann cells
insulate axons, PNS
58
astrocytes
pass nutrients between blood capillaries and neurons, guide neuron development and regulate chemical communication, CNS
58
ependymal cells
line the central canal of the brain and spinal cord (CNS)
59
satellite cells
surround sensory ganglia, PNS
60
dendrites
receive incoming electrical signals, centrally located around a large nucleus
60
axon
part of neuronal process, specialized for long-distance transmission of stimuli, one long axon per neuron, carry impulses AWAY
61
Myelinated nerves
wrapped in myelin sheath (made of schwann or oligodendrocytes), allows for faster conduction, neuroglial cells produce myelin sheath
62
mylin
plasma membrane of glial cells, mostly lipid, segmented made of oligodendrocytes in CNS and schwann cells in PNS, neurilemma is thick outermost coil of myelin sheath that contains schwann cells nucleus
63
how is the presence of myelin sheaths distributed across vertebrates?
lampreys and hagfish lack myelinated neurons but all other vertebrates have them, may have evolved in jawed vertebrates or in ostracoderms
64
multipolar
neuron type, one axon and multiple dendrites, most common neuron type in CNS (receives a lot, few out)
65
bipolar
neuron type, one axon and one dendrite, sensory, common in olfactory cells, retina, inner ear
66
unipolar
neuron type, single process leading away from cell body, sensory cells from skin and organs to spinal cord
67
anaxonic
neuron type, many dendrites but no axon, retina brain adrenal gland (chromaffin cells) all incoming no out going
68
Sensory (afferent) neurons
functional class of neurons, PNS, detect stimuli and transmit information to the CNS
69
interneurons
functional class of neurons, many, confined to the CNS and connect motor and sensory pathways, receive signals from many neurons and carry out integrative functions (make decisions on responses)
70
motor (efferent) neurons
functional class of neurons, PNS, send signals out to the muscles and glands (the effectors)
71
Sensory vs motor neurons
sensory neurons take info from PNS and send it to CNS
motor neurons take info from CNS and send it to PNS
72
Nerve cell regeneration
*some regeneration can occur in PNS if some intact and some neurilemma remains* *process is very slow and come axons connect with wrong fibers*
Axon distal to injury degenerates
Cell body swells; nucleus moves off center due to loss of growth factors from target cell
Axon stump sprouts multiple growth processes
Schwann cells, basal lamina, neurilemma form regeneration tube
Regeneration tube guides new growth
Contact is reestablished with target, cell body shrinks back down
Atrophied muscle fibers regrow
73
Resting membrane potential
difference in charge across the plasma membrane when no signals are being sent
extracellular fluid has more Na+, intercellular fluid has more K+, this causes diffusion and selective permeability, creates an electrical attraction of anions and cations
74
Local potential
change in membrane potential at and nearby point of stimulation
begins at dendrites and spreads to some axons, causes depolarization if enough cells respond
75
Depolarization of local potentials
sodium coming in cancels some of negative charge and membrane voltage drifts closer to zero
76
Action potential
rapid up and down shift in membrane potential that can travel a long distance, triggered by excitatory local potentials when they reach an area with high enough density of voltage gated channels
77
depolarization of action potentials
voltage gated ion channels open and an action potential is produced
78
repolariation
potassium ions exit the cell and repolarize the membrane (return to resting membrane potential)
79
Hyperpolarization
potassium ions slightly overshoot and hyperpolarize before membrane returns to resting potential
80
Synapses
gaps between neuron junctions
1st neuron is presynaptic (releases neurotransmitter)
2nd neuron is postsynaptic (responds to neurotransmitter)
81
neurotransmitter
chemical signals that are generated at synapses
ex) acetylcholine, norepinephrine, serotonin, dopamine
82
meninges
protective physical barrier around brain and spinal cord, protects from pathogens, made of three fibrous membranes (dura mater, arachnoid mater, and pia mater)
83
cauda equina
lumbar region thickens and branches into cauda equina (spinal nerves) in mammals
84
dura mater
outer layer of meninges, forms loose dural sheath (tough and thick)
85
arachnoid mater
middle layer of meninges, five or six layers of looser cells with collagen and elastic fibers, adheres to dura
86
subarachnoid space
between arachnoid mater and pia mater, filled with cerebrospinal fluid (CSF)
87
pia matter
innermost layer of meninges, delicate and transparent, 1-2 layers of cells with collagen and elastic fibers, follows contours of spinal cord
88
Gray matter
center of spinal cord had posterior dorsal horns that receive sensory information and anterior ventral horns that send out motor information, connected by gray commissure and the thoracic region have a lateral horn that contains neurons of the sympathetic nervous system
89
Spinal cord white matter
outer layer of spinal cord, surrounds the gray matter and consists of bundles of axons that course up and down the cord providing communication between different levels of the CNS (long neuron columns/tracts)
90
ascending tracts
part of white matter of spinal cord, carry sensory information up the spinal cord to the brain
91
descending tracts
really long neurons, conduct motor impulses down the spinal cord away from the brain
92
Which spinal nerves transmit which kind of information (sensory/motor)
Sensory information: ascending tracts (white matter), posterior (dorsal) horns (grey matter)
Motor information: Descending tracts (white matter), anterior (ventral) horns (grey matter)
93
Which vertebrates have different spinal cords from the rest
lampreys: spinal cord is thin and avascular, no distinction between white and grey matter (because no myelin)
Gnathostomes: spinal cord has grey matter but many nerve synapses extend into white matter (grey and white matter connected)
Amniotes: nerve synapses are all contained within grey matter, white matter contains only nerve tracts (more tracts means more control over body movements)
94
Endoneurium
covers each never fiber (axon)
95
perineurium
covers a bundle of fibers (fasicle)
96
epineurium
covers each collection of fascicles=nerves
97
nerve organization
endoneurium-> perineurium (fascicle) -> epineurium (nerve)
98
Afferent fibers
part of spinal nerves, enter via dorsal/posterior roots and bring in sensory information
99
efferent fibers
part of spinal nerves, enter via ventral/anterior roots and send out motor information
100
Dorsal root ganglia
collections of nerve bodies whose axons contribute to spinal nerves
101
Sympathetic chain ganglia
paired series of ganglia adjacent to vertebral column or notochord, connect spinal nerves along body axis
102
nerve plexus
complex networks of nerves that are distributed to muscle groups
103
cervical plexus
in the neck, C1 to C5: supplies neck and phrenic nerve to the diaphragm
104
brachial plexus
near the shoulder, C5 to T1: supplies upper limb and some of shoulder and neck
105
lumbar plexus
in the lower back, L1 to L4: supplies abdominal wall, anterior thigh, and genitalia
106
sacral plexus
in the pelvis, L4, L5, and S1 to S4: supplies remainder of lower trunk and lower limb
107
How does the spinal cord differ across vertebrates?
Lampreys: spinal nerves do not merge
Fish & amphibians: dorsal and ventral nerves on spinal cord merge, visceral motor exit dorsal and ventral
Amniotes: dorsal and ventral nerves on spinal cord merge, visceral motor exits through ventral
108
reflex arc
sensory neurons to interneuron to motor neurons (don't travel to brain, just to spinal cord and back)
109
What does the autonomic nervous system do, and what are the two main components
Autonomic: peripheral nerves and ganglia control visceral activity (involuntary); include both sensory and motor components *breath, heart, blood, and digestion
two main components: sympathetic (fight or flight) and parasympathetic (rest and digest)
110
sympathetic nervous system
part of autonomic nervous system
prepares body for action (fight or flight)
Slows digestion, increases heart rate and BP, mobilizes glucose
thoracolumbar outflow
111
Parasympathetic nervous system
part of autonomic nervous system
restores body to restful state (rest and digest)
Stimulates digestion, slows heart rate, drops BP, stores glucose
craniosacral outflow
112
Thoracolumbar outflow
visceral motor neurons depart from thoracic and lumbar regions
113
craniosacral outflow
cranial nerves VII, IX, X along with some visceral motor neurons depart from sacral region
114
Enteric autonomic system
sensory and motor neurons in the walls of the digestive tract (many neurons here; well known in mammals)
*Digestive regulation nerves
myenteric plexus sits in outer wall of smooth muscle
submucosal plexus is located deep within smooth muscle
115
Longitudinal fissure
deep groove that separates hemispheres (center line)
116
gyri
thick folds on brain surface in some mammals (packs more neurons in) folds (increase SA and volume)
117
sulci
shallow grooves between gyri, grooves (increase SA and volume)
118
corpus callosum
thick nerve bundle at base of longitudinal fissure that connects hemispheres (white matter tracts between hemispheres)
119
two lateral ventricles
fluid filled chamber within brain, one in each cerebral hemisphere (double)
120
third ventricle
fluid filled chamber within brain, narrow medial space beneath corpus callosum
121
fourth ventricle
fluid filled chamber within brain, small triangular chamber between pons and cerebellum
122
Interventricular foramen
AKA foramen of monro
pore that connects lateral ventricles to third ventricle
123
cerebral aqueduct
tube running through midbrain that connects third ventricle to fourth ventricle
124
central canal
tube that connects to fourth ventricle and runs through center of spinal cord
125
Choroid plexus
spongy mass of capillaries on the floor of each ventricle (filters CSF from blood)
126
medulla oblongata
most basal part of brainstem
comes from embryonic myencephalon
essentially a pathway to connect body to brain, all ascending and descending fibers connecting brain and spinal cord pass though medulla
houses nuclei of cranial nerves: V-X in sharks, IX-XII in humans
contains centers for visceral, auditory, and proprioceptive reflexes (where body is in space)
127
pons
Anterior bulge in brainstem, rostral to medulla
Develops from metencephalon
Only present in mammals
has peduncles containing: Ascending sensory tracts, Descending motor tracts, Pathways in and out of cerebellum
Cranial nerves V, VI, VII, and VIII (humans)
Sensory roles: hearing, equilibrium, taste, facial sensations
Motor roles: eye movement, facial expressions, chewing, swallowing, urination, and secretion of saliva and tears
128
what are the major trends in evolution of the different brain regions of the hindbrain across vertebrates?
Cerebellum absent in hagfish and rudimentary in lamprey
Cerebellum is large in many fishes because it coordinates sensory lateral line signals – water currents and electrical stimuli
Large in terrestrial vertebrates to coordinate walking
Pons only in mammals
129
what are the major trends in evolution of the different brain regions of the midbrain across vertebrates?
Often large in fishes
Receives direct input from visual system (optic tectum)
Receive visual information in tetrapods, but is smaller relative to other brain regions than in fishes
130
what are the major trends in evolution of the different brain regions of the forebrain across vertebrates?
Forebrain enlarges independently in several groups:
Increased olfaction (hagfish), more complex locomotion or cognitive processing (tetrapods)
131
Cerebellum
Largest part of hindbrain; contains over half of all brain neurons - right and left hemispheres connected by vermis
Functions:Motor coordination and locomotor ability
Also some sensory, linguistic, emotional functions – perceiving space, recognizing objects from different views, directing eye movements, planning and scheduling
Receives lateral line input in fishes
132
midbrain
derived from mesencephalon
Tectum receives sensory information in all vertebrates
Contains motor nuclei of two cranial nerves that control eye movements: CN III (oculomotor) and CN IV (trochlear)
Often most prominent brain region in fishes and amphibians
133
Thalamus
ovoid mass on each side of the brain, relays motor signals from cerebellum to cerebrum, processes information bound for cerebral cortex
134
hypothalamus
forms part of walls and floor of 3rd ventricle
Regulates body functions (thermoregulation, sleep, food intake, metabolism, etc.) through endocrine system and autonomic nervous system
135
Epithalamus
small mass of tissue; includes pineal gland, habenula, forms thin roof over third ventricle
136
Cerebrum anatomy & function
Largest, most conspicuous part of human brain (aka telencephalon)
Sensory perception, memory, thought, judgment, and voluntary motor actions
Two cerebral hemispheres (five lobes each) divided by longitudinal fissure
Connected by white fibrous tract, the corpus callosum
Gyri and sulci in some mammals: increase amount of cortex in the cranial cavity, allowing for more information-processing capability
137
Frontal lobe
voluntary motor functions, motivation, planning, memory, emotion, social cues
138
parietal lobe
integrates general senses, taste, and visual info
139
occipital lobe
primary visual center of brain
140
temporal lobe
hearing, smell, learning, memory
141
insula
lobe of cerebrum, language, taste, visceral sensation
142
Projection tracts
cerebral white matter, vertically connect higher and lower centers (info up/down)
143
commissural tracts
cerebral white matter, cross cerebral hemispheres (info side to side)
144
association tracts
cerebral white matter, connect regions within a hemisphere (info shared on one side)
145
stelate cells
part of the cerebral cortex (grey matter), receive sensory input and process information locally
146
pyramidal cells
part of cerebral cortex (grey matter) include output neurons that leave cortex and connect with other parts of the CNS
147
Reticular formation
Loose web of gray matter that runs vertically through all levels of the brainstem and into the upper spinal cord
Occupies space between white fiber tracts and brainstem nuclei
functions: Somatic motor control – adjust muscle tension for tone, balance, posture; relay signals from sense organs to cerebellum, Cardiovascular control. Pain modulation
148
cingulate gyrus
part of limbic system, arches over corpus callosum in frontal and parietal lobes
149
hippocampus
part of limbic system, in medial temporal lobe (memory functions)
150
amygdala
part of limbic system, immediately rostral to hippocampus (emotion functions such as gratification and adversion)
151
Terminal nerve (O)
arises from olfactory placodes, chemosensory role in regulating reproduction, sensory
152
Olfactory nerve (I)
in mucus membrane of olfactory sac, travels from olfactory bulb and olfactory tract to brain, sensory nerve bringing smell to the brain
153
Optic nerve (II)
develops in CNS of brain, information from retinal neurons to optic lobes of the brain, a sensory tract that brings information about sight from the eye to the brain
154
Oculomotor nerve (III)
innervates extrensic eye muscles and carries visceral motor fibers to the iris and ciliary body, fibers arise from midbrain floor, somatic motor nerve
155
Trochlear nerve (IV)
innervates superior/dorsal oblique muscle, fibers arise in the trochlear nucleus in midbrain but exit from dorsal brainstem, motor
156
trigeminal nerve (V)
mixed nerve, enters at pons and neuronal bodies collect at semilunar ganglion collects sensory from skin of the head and mouth, motor fibers innervate the upper and lower jaw,
157
what are the major branches of the trigeminal nerve?
Ophthalmic division (V1): sensory from upper face (superficial and deep in sharks)
Maxillary division (V2): sensory from middle/lower face
Mandibular division (V3): mixed from lower jaw for chewing
158
Abducens nerve (VI)
innervates extrinsic eye muscles, motor nerve of the lateral rectus, arises in the medulla oblongata, motor nerve
159
Facial nerve (VII)
mixed nerve, Innervates opercular complex in fish
Enters skull through external acoustic meatus and stylomastoid foramen
Five branches to different parts of face in humans; four in sharks
160
branches of facial nerve in humans
Temporal – to temporal region
Zygomatic – runs across zygomatic bone to orbit; joins with maxillary branch of V (V2)
Buccal – pass below orbit to mouth; join with V2
Mandibular – innervates muscles of lower lip and chin
Cervical – descends into neck
161
branches of facial nerve in sharks
Superficial ophthalmic – joins with branch of V to form superficial ophthalmic trunk
Buccal – joins with maxillary branch of V to form infraorbital trunk
Hyomandibular – passes behind spiracle, contains sensory and motor fibers
Palatine – runs forward to the lining of the mouth
162
auditory nerve (VIII)
A sensory nerve that carries information about balance and hearing from the inner ear
Synapses in several regions of the medulla
Enters skull through internal acoustic meatus
163
Glossopharyngeal nerve (IX)
A mixed nerve that supplies the third branchial arch
Returns sensory information from the tongue, outer ear, blood vessels
Sends motor signals related to salivation, swallowing, gagging
Returns to medulla oblongata
164
Vagus nerve (x)
Has the most extensive distribution of any cranial nerve
Major role in the control of cardiac, pulmonary, digestive, and urinary function
Swallowing, speech, regulation of viscera
Additional lateral line nerves sometimes merge with the vagus
mixed nerve
165
Spinal accessory nerve (XI)
Small but distinct motor nerve (ventral) in amniotes that supplies the cleidomastoid, sternomastoid, and trapezius muscles (cucullaris derivatives)
Some fibers accompany vagus nerve to the pharynx, and larynx
Arises from the medulla
In anamniotes, composed of a branch
of the vagus and occipitospinal nerves
166
hypoglossal nerve (XII)
A motor nerve that innervates hyoid and tongue muscles
Originates in medulla
In fishes and amphibians, occipital and spinal nerves merge to form hypobranchial nerve (so no roman numeral)
In amniotes, it is incorporated into the skull as a true cranial nerve
167
embryonic nerve changes from fish to tetrophods
Terrestrial vertebrates have a vomeronasal branch of the olfactory nerve
In non-mammals, most of the optic nerve fibers decussate (cross each other) at the optic chiasm, but in mammals only some of them do - the rest remain on the same side
The lateral line system is completely lost in amniotes, so no lateral line nerves remain
Branches of the trigeminal and facial nerves are different (origin of ophthalmic branch in nerve V; four vs five branches in nerve VII)
168
what makes up a sensory receptor
specialized nerve cells for detecting and transmitting information
Sensory neurons have dendrites to receive stimuli and carry impulses toward the body of the cell
Also have axons to transmit impulses away from the cell
The sensory receptor acts as a transducer - translates information into electrical impulses
169
placodes
ectodermal thickenings where special sense organs develop from, form distinct positions next to neural tube and contribute to special sense organs and to distal cranial sensory ganglia
help make otic, optic, and olfactory sense organs and some cranial nerves
170
What are the 3 general properties of sensory receptors?
transduction, receptor potential, and sensation
171
transduction
general property of sensory receptors, the conversion of one form of energy to another
Fundamental purpose of sensory receptors is to convert stimulus energy (light, heat, touch, sound, etc) into nerve signals
172
receptor potential
general property of sensory receptors, small local electrical changes on a receptor cell caused by a stimulus
Results in the release of a neurotransmitter or a volley of action potentials that generate nerve signals
173
sensation
general property of sensory receptors, a subjective awareness of the stimulus
Most sensory signals delivered to the CNS produce no conscious sensation (i.e. pH and body temperature); are filtered out by brainstem to prevent information overload
Occurs when nerve signal reaches cerebral cortex
174
What are the four kinds of information sensory receptors transmit?
Modality, location intensity, duration
175
Modality
kind of information sensory receptors transmit, type of stimulus or sensation it produces
E.g. vision, hearing, taste; determined by part of brain that receives it
176
location
kind of information sensory receptors transmit, where a stimulus is located
E.g. location being touched; receptive field determines which nerve fibers fire
177
intensity
kind of information sensory receptors transmit, strength of stimulus
E.g. whether a sound is loud or soft; determined by which fibers respond, how many fibers respond, and how fast they fire
178
duration
kind of information sensory receptors transmit, how long the stimulus lasts
Determined by changes in firing frequency
over time - if stimulus is prolonged, firing
of neuron gets slower over time
Phasic and tonic receptors
179
phasic receptors
adapt rapidly with initial burst of action potential (desensitization ex) buttered popcorn)
180
tonic receptors
adapt slowly with steady action potentials ex) pain receptors
181
thermoreceptors
modality, heat and cold
182
photoreceptors
modality, light
183
nociceptors
modality, pain/tissue injury, situations threatening damage
184
chemoreceptors
modality, chemicals (odor, taste, body fluid composition)
185
mechanoreceptors
modality, physical deformation (pressure, inner ear)
186
electroreceptors
modality, electrical stimuli
187
exteroceptors
origin of stimuli, external stimuli, environment
188
interoceptors
origin of stimuli, internal stimuli, organs
189
proprioceptors
origin of stimuli, body position and movement, tendons/muscles/joints
190
general (somesthetic) senses
widely distributed (skin, muscles, joints, viscera)
all across body, not condensed into organs
191
special senses
limited to head (vision, hearing, equilibrium, taste, smell)
192
unencapsulated nerve endings
lack connective tissue wrappings, free nerve endings, tactile discs, hair receptors
193
free nerve endings
unencapsulated nerve ending for pain and temperature, skin and mucous membrane
194
tactile discs (merkel cells)
unencapsulated nerve endings for light touch and texture, sit at base of epidermis
195
hair receptors
unencapsulated nerve endings, monitor movement of hair, coil around a hair follicle
196
encapsulated nerve endings
Nerve endings encapsulated by glia or connective tissue - wrapping enhances sensitivity or selectivity of response
Lamellar corpuscles, tactile corpuscles, end bulbs, bulbous corpuscles
197
Lamellar corpuscles
encapsulated nerve endings, phasic, respond to deep pressure, stretch, tickle, and vibration
Periosteum of bone, and deep dermis of skin
198
tactile corpuscles
encapsulated nerve endings, light touch and texture
Dermal papillae of hairless skin
199
end bulbs
encapsulated nerve endings, tactile, temperature; in mucous membranes
200
bulbous corpuscles
encapsulated nerve endings, — tonic, respond to heavy touch, pressure, joint movements, temperature, and skin stretching
201
referred pain
Pain in viscera often perceived as originating form superficial site
Results from convergence of neural pathways in CNS
The brain cannot distinguish which source the arriving signals are coming from
* inside and outside share same pathway, why in heart attacks left shoulder hurts
202
muscle spindle
used in proprioception, sense body positioning and movement in space, respond to muscle stretching
Are especially abundant in muscles that require fine motor control (e.g. hands)
203
tendon organ
proprioceptors located in a tendon near its junction with a muscle
Respond to tension on tendons
When tendons are slack, collagen fibers are slightly spread and put little pressure on nerve endings
When muscle contracts, collagen fibers come together and squeeze nerve endings
204
basal cells
in olfactory epithelium, differentiate into new cells of any type to replace multicellular mucus glands
205
mitrial cells
reside within olfactory bulb and send signals to the brain down olfactory tract
206
vomernasal organ
nasal sac enlarges between nares to form vomernasal organ, a rich vascular and glandular organ for more smelling, receptive neurons that resemble olfactory neurons, travel to accessory olfactory bulb in the brain
207
Flehmen response
using the vomernasal organ to detect pheremones
208
taste buds
Taste is detected by barrel-shaped clusters of 20-30 receptor and sustentacular cells of endodermal origin
209
lingula papillae
bumps on tongue, have taste buds in them
210
taste pore
connect taste buds which are located beneath epithelial surface
Surfaces contain taste hairs that receive chemicals
Taste bud cells turn over every week or two
Respond to narrower range of chemicals than olfactory receptors
211
rods
photoreceptors that sense illumination
212
cones
photoreceptors that sense colors in bright light
213
sclera
part of outer fibrous layer of connective tissue, white of the eye
214
Cornea
part of outer fibrous layer of connective tissue, anterior transparent region
215
uvea
part of vascular layer, middle layer with choroid (includes tapetum lucidum), ciliary body, and iris
216
retina
part of inner layer of eye, contains rods and cones and three cell layers made of horizontal cells, bipolar cells, amacrine cells, ganglion cells, and fovea
217
cilliary body
tiny circle of smooth muscle that controls visual accommodation- deforms lens
218
pupil
an opening defined by the edge of the iris
219
horizonal cells
inside retina, connects output of rods and cones across retina
220
bipolar cells
first order neurons, synapse with photoreceptors
221
amacrine cells
form connections across retina, affects output of bipolar cells, lie proximally
222
ganglion cells
receive input from bipolar cells, lie proximally
223
fovea
depression in retina that concentrates light, provides sharpest focus
224
vitreous humor
contained in vitreal chamber behind the lens, clear gel like substance that helps eye keep its shape
225
optic disc
where the nerve fibers from the retina converge
226
blind spot
no receptor cells at optic disc, creates a blind spot at back of the eye
227
visual filling
the brain uses surrounding images to fill in blind spot
228
refraction
To focus an image, light rays must be refracted (bent) from their original parallel paths to converge on the retina
229
photopupillary reflex
Pupil dilates or constricts to regulate the amount of light entering
230
emmetropia
focusing on an object far away – light rays are essentially parallel and are easily focused
231
accommodation of the lens
the lens changes curvature to change focus
When the ciliary muscle is relaxed and dilated it puts tension on the suspensory ligament and flattens the lens – distance vision
When the ciliary muscle contracts and narrows it puts less tension on the ligament and the lens takes on a more convex shape – near vision
In some vertebrates (birds and other reptiles) sclerotic ossicles help to focus eye
232
hyperopia
a vision condition in which distant objects are usually seen more clearly than close ones
233
myopia
a vision condition in which people can see close objects clearly, but objects farther away appear blurred
234
monocular vision
where an individual is reliant on only one eye for their vision
235
binocular vision
there is overlap of a portion of the visual world perceived by each eye.
236
scoptic vision
able to see in dim light, many rod cells
237
photoptic vision
color vision in bright light, cone cells
238
trichromatic vision
three types of cones
can see non-primary colors like violet/blue, green, orange
239
dichromatic vision
two cone types; can’t distinguish between yellow, green, and red areas of spectrum
240
pit organs
in snakes, thermoreceptors are suspended in thin membranes or epidermal scales
Labial pits on lips, loreal pits between nostril and eye
241
what are the major steps of eye devlopment
Composite structure formed in part form mesenchyme and the optic placode
Retina is expansion of the brain
Begins with paired outgrowths – optic vesicles – from sides of future telencephalon
As they approach the ectoderm they thicken to become optic placodes and invaginate to form lens primordia
The optic placode pinches off to settle into the optic cup
Surrounding mesenchyme condenses to form the outer layers of the eye
Ectoderm gives rise to eyelid, cornea, and lens, while mesenchyme forms choroid and sclera
242
hair cells
microscopic hair-like projections at the apical surface
243
Stereocilia
(specialized microvilli) tiny processes of unequal length, include a core of fine microfilaments with cross-bridges that behave like a rigid rod (movement triggers action potential)
244
kinocilium
longest process of hair bundle
one per tuft of stereocilia, make up hair bundle
245
neuromasts
small collection of hair cells, supporting cells, and sensory nerve fibers – the most common arrangement of a mechanoreceptor
246
cupula
Projecting hair bundles are usually embedded in gelatinous cap – cupula – that amplifies mechanical stimulation of hair cells
247
lateral line canals
long recessed grooves concentrated on head and extending along the sides of the body and tail contain neuromast organs
248
where are major lateral line canals located on head/body
concentrated on head and extending along the sides of the body and tail
249
vestibular apparatus
in inner ear, covers direction of movements
A balancing organ that arises phylogenetically from part of the lateral line system
Forms embryologically from the otic placode – sinks inwards to produce hair cells, neurons, semicircular canals and connecting compartments
Vestibular apparatus is filled with lymph fluid
250
semicircular canals
part of vestibular apparatus, filled with cristae and ampulla that cover the direction of movement and where body is in space
251
sacculus
inner compartment of vestibular apparatus
252
utriculus
inner compartment of vestibular apparatus
253
cristae
sensory receptors within semicircular canals, expanded neuromast organs with hair cells and cupulla
254
ampullae
base of each canal, expanded with hir cells
255
macula
sensory receptor within saculus and utriculus, has additional calcium carbonate concentrations (the crystals!!)
256
cochlea
the spiral cavity of the inner ear containing the organ of Corti, which produces nerve impulses in response to sound vibrations.
257
lagena
an extension of the saccule of the ear in some vertebrates, corresponding to the cochlear duct in mammals, important for hearing in fishes
258
static equilibrium
*uses gravity
perception of head orientation when body is stationary
When head is tilted, heavy otolithic membrane sags, bending stereocilia and stimulating hair cells
259
dynamic equilibrium
perception of motion or acceleration
linear and angular acceleration
260
linear acceleration
change in a straight line, detected as otoliths lag behind and bend stereocilia
261
angular acceleration
change in rate of rotation, macula sacculi responds to this
262
pinna
external cartilaginous flap covering external auditory meatis, irregular shape helps to distinguish direction of sounds
263
tympanum
= eardrum, a thin and taut membrane, evolved multiple times in tetrapods
264
middle ear bones
stapes (derivative of hyomandibular)
incus and malleus (derivative from quadrate and articular
265
what modifications were made to the ears in the transition to land? why?
Most changes in tetrapods relate to sound traveling in air, rather than water
Impedance matching – fluid is thick, air is thin; different amounts of sound energy needed to vibrate molecules
Easy for fishes in water to pass vibrations to fluid-filled ear, harder for tetrapods
Most airborne sounds that arrive at a fluid are reflected away because greater viscosity of fluid resists being set in motion
Middle ear structures are adapted to equalize vibrations between fluid types:
Sound waves set tympanum in motion, can be over 10X the area of the fenestra ovalis (oval window)
Ossicles act as levers to transmit vibrations to fenestra ovalis
Transform sound waves in air to sound waves in fluid
Amplify the sound
Earliest tetrapods had large stapes but lacked other specializations like enclosed middle ear cavity; tympanum
266
impedance matching
fluid is thick, air is thin; different amounts of sound energy needed to vibrate molecules
267
electroreceptors
Sensory receptors that respond to weak electric fields
Only found in (most) fishes and in monotremes – a vertebrate synapomorphy
Modified neuromast organs located in pits within the skin, concentrated on a fish’s head
ampullary receptors and tuberous receptors
268
electroplaques
Specialized blocks of muscle called electroplaques form an electric organ
269
ampullae of lorenzini
present in elasmobranchs; can localize signals from breathing muscles of prey hiding in sediment
electroreception
270
how do fish use electrical fields to relay information about environment to receptors
Many fishes have electroreceptors, but don’t generate their own electrical fields
Especially concentrated around mouth
respond to changes in electrical amplitude
271
isometry
growth is the same scaling (rare)
272
allometry
change in shape as size changes
ex) babies heads are huge but we grow into them
273
geometric growth)
length is multiplied by a constant in each time interval of growth ex) lobster claw
exponential!
274
arithmetic growth
a constant is added to its length in each time interval of growth ex)lobster body
linear!
275
devlopment
from fertilization to birth or hatching
276
senescence
aging – loss of physical vigor and reproductive ability
Can be quick (e.g. salmon) or slow (e.g. humans)
277
oviparity
laying eggs encapsulated in shells or other egg envelopes
Most fish, reptiles, birds, crocodilians amphibians, monotremes
278
viviparity
giving birth to live young without shells
Most mammals, some reptiles, some amphibians
279
ovoviviparity
(aplacental viviparity) – embryos develop within eggs, inside the mother, until hatching/birth
Some sharks and rays
280
fertilization membrane
Primary envelope includes
the vitelline membrane
Prevents polyspermy
Secondary envelope
consists of ovarian or
follicle cells
Help with nutrient transfer
The tertiary envelope
forms in the oviducts in
some groups
Forms egg shell or egg case
281
zygote
fertilized egg
282
morula
solid ball of cells
283
blastula
hollow ball of cells
284
gastrula
cup-shaped embryo forming 3 germ layers
285
neurula
embryo closing neural tube
286
holoblastic cleavage
furrows pass through the entire zygote (little yolk): amphibians, mammals, some fish
287
meroblastic cleavage
only part of the cytoplasm is cleaved (lots of yolk)
288
yolk sac
endoderm + mesoderm spread around yolk
289
amnion
transparent sac that encloses embryo in fluid
290
allantois
expands from hindgut, develops network of blood vessels for gas exchange or umbilical cord in mammals
291
chorion
is outermost membrane, surrounds all other membranes
292
metamorphosis
radical and abrupt postembryonic change in structure to become adult
Aquatic to terrestrial, motile vs sessile, tail vs limbs
Lampreys, some fish, many amphibians
293
direct development
young embryo develops directly into miniature adult
Lots of amphibians, e.g. Raorchestes frog
Reptiles, birds, mammals
294
heterochromy
different timing of development, includes peramorphosis and pedomorphosis
295
peramorphosis
adult characters are exaggerated or extended in shape
296
pedomorphosis
juvenile characteristics of ancestors appear in adults of the descendants
297
what are some ways that animals adjust to scaling changes when size increases
Change proportions of different body parts to adapt to current environment/life history
Longer out levels are associated with faster speeds (e.g. running)
Longer in levers are associated with greater force (e.g. digging)
298
Gastrulation
formation of gut and three tissue layers, has invagination, epiboly, involution, ingression, and delamination
299
invagination
a wall of cells turning inward – non-vertebrate chordates
300
epiboly
cells spread across outer surface – fishes, amphibians, birds
301
involution
cells turn inward and spread over internal surface – amphibians, reptiles
302
ingression
surface cells migrate internally – birds and mammals
303
delamination
sheets of cells splitting into parallel layers – many groups
304
What are the major tissues formed form each of the germ layers?
Endoderm: Lining of the digestive tract and associated organs Lungs
Mesoderm: Bones Muscles Heart, blood, and kidneys
Connective tissues
Ectoderm: epidermis, neural crest, neural tube
