Vet Term Flashcards
(174 cards)
1
Q
What are 7 functions of muscles?
A
locomotion respiration digestion parturition blood and lymph circulation swallowing generation of body heat
2
Q
what are the 4 specific properties of muscles?
A
contractility= ability to contract or shorten excitability= capacity to receive and respond to a stimulus extensibility= ability to be stretched elasticity= ability to return to original shape after being stretched
3
Q
what are three types of muscles?
A
skeletal
smooth
cardiac
4
Q
5 main characteristics of smooth muscle
A
no striations central nucleus contracts slowly found in viscera, blood vessels control is involuntary
5
Q
5 main characteristics of skeletal muscle
A
striations peripheral nuclei contracts rapidly found in trunk, extremities, head and neck control is voluntary
6
Q
5 main characteristics of cardiac muscle
A
striations central nuclei contracts rapidly found in heart control is involuntary
7
Q
what is body movement a result of?
A
contraction of skeletal muscle across a movable joint
8
Q
what is body movement stimulated by?
A
a motor nerve under voluntary control
9
Q
where is skeletal muscle attached, and how? what is its main function?
A
attached to bones by tendons
moves and supports the skeleton
10
Q
Skeletal muscles are described according to what?
A
according to the type of movement performed
11
Q
flexors location and what does contraction lead to?
A
located on the side of the limb toward which the joint bends when decreasing the joint angle
contraction leads to flexion of the joint
12
Q
Extensors location and what does contraction lead to?
A
located on the side of the limb toward which the joint bends when increasing the joint angle
contraction leads to the extension of the joint
13
Q
adductors location and what does contraction lead to?
A
muscles that pull a limb toward the median plane
contraction leads to adduction of the limb
14
Q
abductors location and what does contraction lead to?
A
muscles that pull a limb away from the median plane
contraction leads to abduction of the limb
15
Q
sphincters definition
A
muscles arranged circularly to constrict body openings
16
Q
epimysium definition
A
sheath of connective tissue surrounding the muscle
17
Q
fascicle definition
A
a small bundle or cluster of muscle fibers (cells)
18
Q
perimysium definition
A
connective tissue extensions from the epimysium that surround each fascicle
19
Q
endomysium definition
A
connective tissue extensions from the perimysium that surround the muscle fibers and are attached to the sarcolemma
20
Q
sarcolemma definition
A
a thin membrane enclosing a skeletal muscle fiber (cell)
21
Q
muscle fibers definition
A
muscle cells- elongated shape, multinucleated
22
Q
what is the name for a muscle cell?
A
morphological syncytium
23
Q
what is the pull of a muscle filer transmitted by (3) and what is it pulled to (2)?
A
endomysium, perimysium and spimysium to tendon or aponeurosis that is attached to the bone
24
Q
what is the pathway of a fiber to connection to bone?
A
sarcolemma fuses with tendon fibers- collect into bundles to form muscle tendons- connect to the muscles to the bone
25
what are myofibrils composed of?
composed of linear series of repeating sarcomeres
26
how many myofibrils are in each muscle fiber?
several hundred to thousands
27
what are sarcomers, what do they contain, and what does their arrangement give rise to?
basic contractile unit of striated muscle fibers
found between z lines, and contain protein myofilaments (actin and myosin)
arrangement gives rise to striations
28
what are myofilaments responsible for?
actual muscle contraction
29
what makes up the thin (3) and thick (1) filaments of myofilaments?
```
thin= actin, troponin and tropomyosin
thick= myosin
```
30
what is sarcoplasmic reticulum and what is its function?
specialized ER
important for muscle contraction
regulated calcium storage, release and re-uptake
31
where are mitochondria located in muscle cells and that do they supply myofibrils?
lie parallel to the myofibrils
| supply large amounts of energy= ATP
32
how are t-tubules arranged and what is their function?
arranged transversely to the myofibril
allow the plasma membrane of the muscle fiber to carry the depolarization of the action potential to the interior of the fiber
33
what are 5 characteristics of smooth muscle that are distinctive in each organ?
```
physical dimensions
organization into bundles or sheets
response to different stimuli
characteristics of innervation
function
```
34
what are the two categories of smooth muscle?
multi-unit
| single-unit
35
what are 3 characteristics of multi-unit smooth muscle?
discrete, separate smooth muscle fibers
each muscle fiber contracts independently
innervated by a single nerve ending
36
where are 5 locations of multi-unit smooth muscle?
```
ciliary muscles of the eyes
iris muscle of the eyes
base of hair follicles
smaller airways to lungs
walls of large blood vessels
```
37
what are 3 other names or single-unit smooth muscle?
visceral
syncytial
unitary
38
how are the fibers arranged in single-unit smooth muscle?
arranged in sheets or bundles
| cell membranes are adherent to one another
39
how do single-unit smooth muscle fibers contract and how is it done?
contract together as a single unit
| the force generated in one muscle fiber can be transmitted to the next
40
how are cell membranes of single-unit smooth muscle joined?
by gap junctions
41
where are 5 locations of single-unit smooth muscle?
```
GI tract
bile ducts
ureters
uterus
blood vessels
```
42
what are actin filaments attached to in smooth muscle, and where are they located (2)?
dense bodies
1. attached to cell membrane- bound together by intercellular protein bridges
3. dispersed inside the cell
43
where are myosin filaments located in smooth muscle?
interspersed among the actin filaments
44
what is a characteristic of myosin filaments and what is its function?
side-polar cross-bridges
bridges on one side bend in one direction and those on the other side bend in the opposite direction- allows myosin to pull an actin filament simultaneously in opposite directions
45
how much of their length can a smooth muscle contract compared to skeletal muscle?
```
smooth= 80%
skeletal= 30%
```
46
what is the major source of Ca in smooth muscle contraction
ECF
47
where are sarcoplasmic reticulum located in the smooth muscle?
near the cell membrane in some larger smooth muscle cells in small invaginations (cavolae)
48
more extensive sarcoplasmic reticulum means what for the smooth muscle fiber?
more rapidly it contracts
49
what is cardiac muscle
functional syncytium
50
what is a characteristic of cardiac muscle during development?
myocytes branch or bifurcate during development and bind to other myocytes
51
how are fibers arranges in cardiac muscle and how are they connected?
remain separated as distinct cells with their respective sarcolemma
electrically connected to each other through intercalated disks
52
what is an intercalated disk?
dark, dense cross-band found in the ends of each myocardial cell
53
what types of cell-cell junctions are present in intercalated disks? (2)
gap junctions
| desmosome
54
what is the role of gap junctions (2) and desmosomes (1) in intercalated disks?
gap: allow rapid diffusion of ions and action potential travels easily from one cell to the next
desmosome: provide mechanical strength
55
what are the two categories of cells in the nervous system?
Neurons
| neurogila
56
what is the major functional unit of the nervous system and what is it specialized in?
neurons
| nerve cells are specialized in information processing
57
what are the 7 components of neurons and what is their function?
1. dendrites: info receiving area of the cell membrane
2. cell body/soma/perikaryon: contains organelles
3. axon: info carryng extension of the cell membrane
4. axon hillock/trigger zone: axon origin, originates AP
5. presynaptic terminal: end of axon, transmit info
6. myelin sheath: enhances speed f info transfer
7. node of ranvier: gaps in the insulating myelin sheath
58
how to neurons communicate?
via synapses
59
what 3 things do neurons connect with for communication?
neurons, muscle fibers, glands
60
Where is the connection between neurons formed?
by the presynaptic terminal of one cell, the receptive surface of the adjacent cell (postsynaptic cell) and the space between the two cells (synaptic cleft)
61
Where do action potentials travel, and at what speed?
travels along the axon at 05.5-120 meters/sec
62
are larger or smaller neurons myelinated?
larger
63
what is the myelin sheath, and where is it located?
modified plasma membrane
| wrapped around the axon in a spiral form
64
where are two locations that the myelin sheath originates from and are a part of?
schwann cells in PNS
| oligodendrocytes i the CNS
65
What are the nodes of raniver?
periodic interruptions between myelin segments of the axon
66
what to schwann cells in the cytoplam form?
a ring inside and outside the sheath
67
what does the myelin sheath facililtate and what does it classify it as?
facilitates conduction
| it is an electrical insulator
68
what type of conduction does the myelin sheath allow and what does it effect?
allows saltatory conduction
action potential jumps from node to node
depolarization is much more rapid than in unmyelinated fibers
69
what is conduction velocity in myelinated fibers proportional to and what does that mean for larger axons?
proportional to the diameter
| larger axons have loner internodes and faster conduction velocities
70
what is unmyelinated fibers conduction proportional to?
the square root of the diameter
71
myelin facilitates conduction while conserving what two things?
space and energy
72
what two categories can neurone be classified as?
structure and function?
73
what are the three categories of function for neurons?
sensory/afferent
interneurons/association neurons
moror/efferent
74
what is the role of sensory/afferent neurons?
send info from receptors towards the brain/spinal cord
75
what is the role of interneurons/association neurons?
found in the brain/spinal cord, connecting motor and sensory neurons
76
what is the role of motor/efferent neurons?
send info from the brain/spinal cord to muscle/glands (effectors)
77
what are the three structures of neurons?
unipolar
bipolar
multipolar
78
what is the structure of unipolar neurons and what type of neurons are they?
have a single stem process that bifurates to form 2 processes (peripheral and central)
sensory neurons
79
what is the structure of bipolar neurons and what type of neurons are they?
have 2 processes (1 axon, 1 dendrite)
| interneurons
80
what is the structure of multipolar neurons and what type of neurons are they?
have numerous cell processes (1 axon and many dendrites)
| motor neurons
81
which structural neuron is the most common?
multipolar neuron
82
what are two things that nurogila cells don't do?
don't produce action potentials
| don't participate directly in synaptic interactions and electrical signaling
83
what are 5 characteristics of nurogila cells?
smaller than neurons
don't have axons and dendrites
fill all spaces in the NS not occupied by neurons or blood vessels
more numerous than neurons in the nervous tissue
have the capacity to divide
84
what are 5 roles of neurogila cells int e NS?
production of myelin sheaths of axons
modulate the growth of developing or damaged neurons
buffer extracellular concentrations of potassium and neurotransmitters
participate in the formation of contacts between neurons (synapses)
participate in certain immune responses of the nervous system
85
what are types of glial cells? (CNS 4 vs PNS 1)
CNS: microglial cells, astrocytes, oligodendrocytes, ependymal cells
PNS: schwann cells
86
What are 3 roles of microgilia cells?
the brain's immune system
protect the brain against injury and infection
play a role in the developing brain
87
what are two ways that microgila cells act as the brain's immune cells?
act as macrophages= phagocytosis to clear debris
| release NO and H2O2 to prevent viral replication
88
how to microglia cells play a role in the developing brain?
help to destroy the synapses that are unnecessary
89
what is the structure of astrocytes and what percentage of them make up the glial population in CNS?
star-shaped cells with numerous long cell processes
| 50% population
90
what is the role of astrocytes?
provide structural and metabolic support to the CNS
91
What are 4 examples of the role of astrocytes?
form outer and inner glial limiting membranes of the CNS
release neurotrophic factors important for neuronal survival
help elongate axons and dendrites
participate in the repair processes following tissue injury
92
what is the role of oligodendrocytes?
provide support to axons of neurons in the CNS
93
Oligodendrocyted have numerous processed to do what?
extend to adjacent axons to form myelin
94
what is brain white matter and what is gray matter?
```
white= myelin sheath
gray= areas with high population of soma
```
95
where are ependymal cells located?
conver the ventricles of the brain, central canal of the CNS, and choroid plexus in the 4th ventricle of the medulla oblongata
96
what is the role of ependymal cells?
involved in creating cerebrospinal fluid
97
what is another name for schwann cells?
neurolemmocytes
98
how are schwann cells arranged and what does each cell form?
side by side along the axon
| each cell forms internodes of myelin sheath of various length
99
what is the role of schwaan cells?
provide support to axons of the PNS by producing myelin in axons
100
what are the two major subdivisons of the nervous system?
central nervous system
| peripheral nervous system
101
what is the CNS composed of and what are each surrounded by?
brain- surrounded by the skull
| spinal cord- surrounded by a series of cervical, thoracic and lumbar vertebrae and ligaments
102
what are the 7 major regions of the CNS?
```
spinal cord
medulla (oblongata)
pons
cerebellum
midbrain/mesencephalon
diencephalon
telencephalon/cerebral hemispheres
```
103
what is the CNS protected by? (2)
meninges and cerebrospinal fluid
104
what are the 3 protective layers of the CNS?
pia mater
arachnoid
dura mater
105
where is pia mater located?
innermost menigeal layer, lies next to the CNS
106
where is arachnoid located?
spiderweb appearances, traps cerebrospinal fluid
| subarachnoid space
107
where is dura mater located?
outer most meningeal later
often fused with the inner surface of the skull
thicker
108
where is cerebrospinal fluid found within? (3)
subarachnoid space
central cana of the spinal cord
ventricular system of the brain
109
what are 2 roles of cerebrospinal fluid?
determinant of neuronal microenvironment (provide micronutrients, carries away metabolic waste)
chock absorber for the CNS
110
where is cerebrospinal fluid produced?
in the ventricles of the brain
111
what is the peripheral nervous system composed of?
all the neural tissue outside the CNS
112
what are two functions of the PNS?
deliver sensory information to the CNS
| carry motor commands to peripheral tissues and systems
113
what is peripheral nerve fiber and what is it surrounded by?
axon and myelin sheath (if present) together
| surrounded by connective tissue= endoneurium
114
what is fascicle and what is it surrounded by?
a bundle of nerve fibers
| surrounded by connective tissue= perineurium
115
what is nerve (cranial or spinal) and what is it surrounded by?
a bundle of fascicles
| surrounded by connective tissue = epineurium
116
where are cranial nerves?
innervate parts of the head and connects directly to the brain
117
where are spinal nerves?
innervate much of the body and connect to the spinal cord
118
what are two categories of the nerves of the PNS?
motor (efferent)
| sensory (afferent)
119
what two categories are motor nerves separated into and where do they go?
```
somatic= to skeletal muscle
visceral= to cardiac muscle, smooth muscle, exocrine glands
```
120
what two categories are sensory nerves separated into and where do they come from?
```
somatic= from skin, muscle, retina, membranous labyrinth
visceral= from thoracic organs, abdominal organs, olphactory epithelium, taste buds
```
121
definition of systole
contraction and emptying of the heart
122
definition of diastole
relaxation and filling of the heart
123
definition of cardiac output
the total volume of blood pumped by the heart per minute
124
definition of heart rate
number of heart beats per minute
125
definition of tachycardia
increase in heart rate
126
definition of bardicardia
decrease in heart rate
127
what is cardiovascular physiology?
the study of the heart, the blood vessels and the blood
128
what is the cardiovascular system formed by and what is its primary function?
formed by the heart and a vast array of blood vessels
| primary function is transport to maintain homeostasis
129
where is the heart located?
within the throacic cavity in the mediastinum (central compartment)
protected by ribs
130
what are the four chambers of the heart?
R & L atrium
| R & L ventricle
131
what are atria and ventricles separated by?
atrioventricular valves
132
what is the left AV valve called?
mitral valve
133
what is the right AV valve called?
tricuspid valve
134
what is positioned between the ventricles and the great arteries?
semilunar valves
135
what is the aortic valve between?
L ventricle and the aorta
136
what is the pulmonary valve between?
R ventricle and the pulmonary artery
137
what are two characteristics of the structure of the atrium?
thin walled, low pressure chamber
138
What are the three main functions of the atria?
elastic reservoir and conduit from the venous bed to the ventricle
booster pump enhancing ventricular filling
assist atrioventricular valve closure before ventricular systole
139
what are two characteristics of ventricles?
comprise most of the heart's weight and supple the main pumping force
140
What does the right ventricle propel blood through?
the pulmonary circulation
| pulmonary artery
141
what does the left ventricle propel blood through?
the systemic circulation
| aorta
142
what are the three different cell types of cardiac cells?
working myocaridal cells/ myocardium
pacemaker cells
conduction cells
143
what are myocardial cells?
strated muscle specialized for contraction and impulse conduction
144
what are pacemaker cells?
exhibit automatic rhythmical electrical discharge in the form of action potentials
145
what are conduction cells?
conduct the action potentials through the heart providing an excitatory system that controls the rhythmical beating
146
what is the normal pacemaker of the heart?
sinoatrial (SA) node
147
where is the SA node located and what does it initiate?
in the R atrium, below and lateral to the opening of the cranial vena cava
initiates the AP that is conducted throughout the heart
148
where are slower pacemakers located? (2)
in the AV node and his-purkinje system
149
When may the slower pacemakers be used? (3)
when the normal pacemaker:
fire more rapidly than normal
fire slower then normal
impulses generated in the SA node are blocked
150
what is the sinus node?
a small strip of specialized cardiac muscle cells
151
what does the sinus node connect with and what does this allow?
atrial muscle fibers
| allows any AP to spread immediately into the atrial muscle wall
152
what is a characteristic of the fibers in the sinus node?
fibers have almost no contractile muscle filaments
153
How does the AV node affect impulse conduction?
delays impulse conduction from the atria to the ventricles
154
where is the AV node located?
in the posterior wall of the R atrium behind the tricuspid valce
155
what does the delayed transmission of the AV node allow and why does this occur?
allows time for the atria to empty their blood into the ventricles before ventricular contraction begins
occurs because these fibers have less gap junctions
156
what leads the AV node impulse through the AV bundle into the ventricles?
special purkinje fibers
157
what is another name for the AV bundle?
bundle of his
158
what is the role of purkinje fibers?
fast transmission velocity through the remainder of the ventricular muscle
159
what does the AV bundle allow?
only forward conduction from the atria to the ventricles
160
what is the atrial muscle also separated from the ventricular muscle by and what does it act as?
continuous fibrous skeleton
| an insulator to prevent passage of cardiac impulse between atrial and ventricular muscle through abnormal routes
161
what direction do AV bundles pass?
downward in the ventricular septum to the apex and divide into left and right bundle branches
162
where do the branches of the AV bundle lie?
beneath the endocardium
163
What happens to the ends of the purkinje fibers?
penetrate the muscle mass and become continuous with the cardiac fibers
164
what are the 3 steps of the blood flow through the right side of the heart?
deoxygenated blood from the body returns to the heart through the cranial and caudal vena cava
it flows into the R atrium and flows into the R ventricle
Blood pumps through the pulmonary arteries to the lungs to be oxygenated
165
what are the 3 steps of the blood flow through the left side of the heart?
oxygenated blood returns through the pulmonary veins
it flows into the L atrium and then into the L ventricle
blood is pumped through the aorta to the rest of the body
166
what is the role of AV valves
to prevent back flow of blood from the ventricles to the atria during systole
167
how do the AV valves open and close and what triggers them?
passively
open when forward pressure gradient forces blood in the forward direction
close when a backward pressure gradient pushes blood backward
168
what is the significance of the closing of the AV valved?
1st heart sound (long lasting lub)
169
What are AV valves attached to and by what?
attached to the papillary muscles by the chorda tendinea
170
what is the role of papillary muscles?
pull vanes of the valves inward toward the ventricles during systole to prevent their bulging too far backward toward the atria
171
what is the role of the Semilunar valves
prevent back flow from the aorta and pulmonary arteries to the ventricles during diastole
172
what is the important characteristic of Semilunar valves?
resist a lot of physical stress
173
what are three features of the semilunar valve?
no support by the chordae tendinaea
smaller openings- rapid ejection (mechanical abrasion)
higher pressures in the arteries during systole- snap closed
174
what is the significance of when the semilunars close?
2nd heart sound (rapid snap: dub)
