1st Test Material Flashcards
1
Q
Chemicals that stimulate action potentials in postsynaptic cells are called
A
neurotransmitters
2
Q
This organ receives only sympathetic innervation
A
- adrenal medulla
- arrector pili muscles in skin
- most blood vessels
3
Q
Action potentials would be conducted most rapidly by
A
- 40 nanometer diameter myelinated axon
(largest and myelinated)
4
Q
How does plasms glucose move across the BBB?
A
Through carrier proteins GLUT1
5
Q
Ther person who memorized Pi to 22,514 digits is
A
Daniel Tammet
6
Q
Wuth respect to protection of the central nervous system (CNS) the meningal layers protecting the spinal cord from outside (closest to abdomen) to inside (nearest the cord) are…
A
Dura mater. arachnoid mater, pia mater
7
Q
The falling phase of an action potential results from
A
Efflux (flowing out) of K+
8
Q
Parasympathetic receptor
A
Cholinergic
9
Q
Terminal boutons are
A
Presynpatic axon endings
10
Q
What is nervous system structure?
A
Anatomy
11
Q
What is nervous system function
A
Physiology
12
Q
What are the two main divisions?
A
Central Nervous System (CNS): brain and spinal cord
Peripheral nerves and ganglia: peripheral nervous system (PNS)
13
Q
Nervous system function
A
Physiology
14
Q
What is the minimal functional “unit” of nervous system and what is it considered as
A
Neuron; “Neuron Doctrine”
15
Q
What is the fundamental concept of the nervous system?
A
Nervous system is made up of discrete individual cells
16
Q
Is physiology associated with anatomy in the nervous system?
A
Yes
17
Q
What do neurons do?
A
- Conduct “Electrical” Signals (Action Potentials)
- Release “Chemical” Signals (Neurotransmitters)
Therefore- much of what the nervous system “does” (ie neurophysiology) depends on where these processes occur (ie neuroanatomy)
18
Q
What are the 3 functions of the nervous system?
A
- Control of movement and some functions= Motor nerves
- Detection of external stimuli=Sensory nerves
- Integration of neuronal activity and connections (“circuitry”): Association Neurons; these are the neurons within the CNS responsible for behaviour, thought, emotions etc.
19
Q
Why study neurophysiology?
A
- To understand inherited and acquired diseases
- To understand drug modulation
- Since it is interesting
20
Q
What is a neuron?
A
Functional unit of the nervous system
21
Q
What makes up a neuron?
A
Cell body, dendrites, axon
22
Q
What do dendrites do?
A
Recieve info from sensory receptors (or from other cells) and send it to cell body
23
Q
What do axons do?
A
Axons deliver electric signals from the cell body to another neuron or an effector organ (eg a muscle)
24
Q
What does a neuron do?
A
Performs the function of moving “info” rapidly by conducting electrical impulses called action potentials from one location to another, then convering electrical impulse to chemical signal at a synapse
25
Where do sensory of afferent neurons go?
Neurons conduct impulses from sensory receptors INTO the CNS
26
Where do association or interneurons go?
Located entirely within the CNS and help integrate CNS functions, send signals from one neuron to another (middle man) in brain CNS
27
Where do motor or efferent neurons go?
Conduct impulses from sensory receptors OUT of CNS (to effector organs like muscles or glands)
28
What are somatic motor neurons?
Reflex and voluntary control of skeletal muscles
29
What are autonomic motor neurons?
Involuntary control of smooth muscle, cardiac muscle and glands
30
What do autonomic nerves get split into?
Sympathetic and parasympathetic
31
What are the 4 types of Neurons?
1. Pseudopolar (unipolar), sensory, 1 process that splits
2. Bipolar, retinal and cochlear, 2 processes
3. Multipolar, most common, motor and association, many dendrites but one axon
4. Anaxonic, some CNS neurons, no obvious axon (just body with dendrites star shape)
32
T or F. There are at least as many supporting cells as there are nerve cells in the human brain
True 10^11-10^12
33
What are the supporting cells called?
Supporting cells
34
What are the types of supporting cells in the PNS?
Schwann cells: form myeling sheaths around PNS neuron axons
Satellite cells: support neuron cell bodies within ganglia of the PNS
35
What type of supporting cells are there in the CNS?
1. Oligodendrocytes:form myelin sheaths around CNS neuron axons (like Schwann cells in PNS)
2. Microglia: migrate through CNS and phagocytose debris
3. Astrocytes: help regulate external environment of neurons in CNS
4. Ependymal cells: line ventricles (cavities) of brain and spinal cord
36
What is one difference between structural classification of neruons in the PNS and CNS?
PNS: scwhwann cell membrance around one axon, cytoplasm on outside
CNS: one oligodendrocyte forms myelin sheaths around several axons
37
What is the most abundant glial cell in the CNS?
Astrocytes: making up 90% of the nervous tissue in some areas of the brain. Processes termiate in "end feet" at capilaries, others are neurons (axon, cell body, or dendrite) thus they can influence interactions between neurons and blood
38
What do astrocytes do?
1. Take up K+ from ECF (diffuses from neurons during nerve impulses), may help maintain proper ionic envrionment for neurons
2. Can take up neurotransmitter glutamate and transform it to glutamine, which can be released back into neurone, which can use it to refrom the neurotransmitter glutamate
3. "End-feet" surrounding blood capillaries take up glucose from blood, metabolize it to lactate, then release it for use as an energy source by neurons, which metabolize it aerobically into CO2 and H2O for production of ATP
4. They form synapses in the CNS
5. Astrocytes regulate neurogenesis in the adult brain (needed for stem cells to differentiate into both glial cells (all the diff types) and neurons)
6. Help in the formation of BBB
7. Release neurotransmitters (glutamate, ATP, adenosine, D-serine, others) that can stimulate or inhibit activity of neurons
39
If you inject a green dye into the bloodstream, what happens to all tissues but the brain?
All tissues turn green, except for the brain
40
Capillaries in the brain, unlike those of most other organs, do not have...
Pores between adjacent endothelial cells (cells that make up walls of the capillaries), instead the endothelial cells of the capillaries are joined by tight junctions
41
What can move through easily in the BBB?
Nonpolar O2 and CO2 can move through, and organic molecules such as alcohol and barbiturates can pass through the phospholipid components of the plasma membrane. Other moleucles have to go through specific processes (eg active transport, endocytosis)
42
What do astrocytes influence?
The structure and function of the BBB
43
How does nicotine work?
Binds to acetylcholine receptors, other components in tobacco smoke decrease MAO activity (can cause behavioural problems)
44
What are some smoking health risks?
- Cardiovascular disease
- Cataracts and loss of eyesight
- Atherosclerosis
- Reduced fertility
- Reduced life expectancy
- Chronic obstructive pulmonary disease
- Cancers
- Peridontal disease
- Asthma
- Ageing and facial wrinkles
- Ulcers
45
So why do people still smoke?
Populalrity
46
What does drinking alcohol do to your brain?
CNS depressant, directly affects brain cells, affectd areas involved in inhibiting behaviours (animated, talkative, social) Also altered speech, slowed reaction time, foggy memory. Reactions depend to some part on dose, size, weight, gender, genetic etc
47
What does tylenol do?
Inhibition of NO through a variety of neurotransmitter receptors including N-methyl-D-aspartate and substance P (these stop NO)
48
What is rabies?
Deadly viral infection- bit by an infected animal, virus enters the brain, immune cells and antibodies cant enter the brain, no treatmen after symptoms appear, but rapid treatment with anti-rabies antibodies can help attentuate the infection (before it starts affecting them)
49
What types of conditions are helped by drug treatments of the BBB
- Brain cancer
- Parkinsons
- Alzheimers
- Dementia
50
Have doctors been able to get into a brain non-invasively?
Yes, use focused ultrasound to noninvasively treat brain tumours and to treat Alzheimer's and Parkinsons
- MRI found the tumour and ultrasound to disrupt
51
What is the somatic nervous system?
Have cell bodies in the CNS and send axons to skeletal muscles (usually those under voluntary control) eg to conduct impulses along a SINGLE axon from the spinal cord to the neuromuscular junction
52
What is the autonomic nervous system?
Involves two neurons in the efferent pathway. 1st- cell body in the CNS gray matter (brain or spinal cord), axon does not directly innervate the effector organ, but instead synapses with a 2nd neuron in this pathway, called a postganglionic neuron, that has an axon that extends from autonomic ganglion to an effector organ, where it synpases with the target tissue
53
What does autonomic nervous system do?
Helps regulate the acitivities of glands, smooth muscles, and cardiac muscle
54
What does ANS further subdivide into?
1. Parasympathetic Divsion
2. Sympathetic Division
55
Parasympathetic Nervous System (PSNS)
Rest and Digest
56
Sympathetic Nervous System
Fight or flight (sympath for fight or flight)
57
Do most organs recieve input from both systems?
Yes
58
Do PSNS and SNS mediate opposing responses in effector organ
Yes
59
Organs without dual innervation (ones that do not recieve from both sympathetic and parasympathetic)
- Adrenal medulla
- Arrector pili muscles in the skin (muscle associated with hair that makes your hair "stand on end")
- Sweat glands in the skin
- Most blood vessels
In these cases, regulation is acheived by increases or decreases in the tone (firing rate) of the sympathetic fibers
60
What neurotransmitters are released across the synapse?
- Acetylcholine (ACh)
- Norepinephrine (NE)
Cholinergic neurons= release ACh
- Adrenergic neurons= release NE (or E)
ACh and NE bind different receptors to mediate target organ response
61
What is the difference between preganglionic and postganglionic axons between sympathetic and parasympathetic
Parasympathetic: cholinergic
Sympathetic:cholinergeric and adrenergic
62
What does lyme disease cause?
Dysfunction of the ANS
63
What can dysautonomia (dysfunction of ANS) be caused by?
Brain injury, diabetes, genetics etc
64
What happens when someone is bit by a tick?
Bit by an infected tick, the saliva disrupts the local immune response. Spirochetes multiply in the skin
65
What does the immune response cause in humans?
Immune response causes the circular lesion, but neutrophils which are necessary to eliminate the infection fail to appear, bacteria spread via the bloodstream to joints, heart, nervous system, and distant skin sites
66
What does Long COVID-19 cause?
Dysautonomia and POTS (postural orthastatic tachcardia syndrome racing heart)
67
What is synesthesia?
Common form grapheme, or colour synesthesia, or colour-graphemic synesthesia) letters or numbers are percieved as coloured
68
What is the term where musicians hear music as colours?
Chromothesia
69
What is the term where coloured sounds taste sweet
Synaesthesia
70
The average person can hold how many working digits?
7
71
Shigeru Kondo and Alexander Yee got the record for?
10 trillion decicam places
72
Daniel Tammet?
He memorized 22,514 digits in just over 5 hours
73
How thick is the cell membrane?
2 phospholipid molecules thick
74
The cell membrane-fluid mosaic model?
Contain glycolipid, glycoprotein, cholesterol, phospholipid heads and tails
75
Can molecules get across the cell membrane easily?
No, it is a barrier
76
What is one way cells cross the membrane layer?
Simple diffusion (passive): process that does not consume energy; small uncharged molecules (relatively lipid soluble) can diffuse through the lipid bilayer (eg steroid hormones)
77
Can small charged molecules (ions) pass through?
Yes, through water-filled pores (since water is polar)
78
Are some simple diffusion ion channels gated?
Yes, some are voltage gated, can only be opened or closed by gates
79
What is active transport?
Against gradients, active transport needs metabolic energy (usually ATP), eg Na+/K+ ATPase (moves Na+ out of cell), moves K+ into cell
Primary active transport
- Direct consumption of ATP
80
Explain endocytosis, exocytosis, phagocytosis... and so on
Cell drinking, vesicle releases, cell macrophage engulfs bacteria
81
What can integral membrane proteins act as?
Transporters
82
What is the potential difference of voltage across the membrane called?
Resting membrane potential
83
The inside of the cell is what charge compared to outside? What is the resting?
Negatively; -70mV
84
Why are voltage gated ion channels important?
For electrical activity in axons since when the channels open can change the membrane potential of the cell; what is needed to conduct an electrical signal in neurons
85
Where does Na+ and K+ start?
Na+ starts outside, K+ inside at start of action potentials
86
What are action potentials?
Signals that go along the nerves, taking the signal from one place to another
87
What is the plastination technique?
Nervous system preserved using Dr Von Hagens technique
88
What is a primary function of nerve cells?
Recieve, conduct and transmit signals, neurons propogate signals in the form of action potentials
89
What are action potentials?
Momentary discharges (depolarizations) of the resting membrane potential caused by a rapid influx of Na+ caused by the opening of sodium ion channels; once intiated move along axon membrane toward the synpase (the end)
90
Do signals have to go a long way without weakening?
Yes, signals need to be reamplified along the way, to do this use voltage-gated ion channels
91
How does ion gating work with axons?
A. Channel closed at resting membrane potential
B. Gated channel opens in response to depolarization
C. Gated channel closes (ball and chain)
92
What is hypopolarization or depolarization?
If stimulation causes positive charges to flow into the cell, cell becomes more postive
93
What is depolarized number?
+30 mV, once reaches Na+ channels close, rapid decrease in Na+ permeability
94
What do cells do to help compensate the depolarization?
Cell needs to depolarize, K+ will diffuse out of cell, making the inside of the cell less positive (or more negative again), restoring the original resting membrane potential
95
How do Na+ and K+ pumps work?
Pump out Na+ that entered the axon during an action potential and pump in K+ that had left
96
What are the gated Na+ and K+ channels said to be since they are stimulated by depolarization?
Voltage-regulated channels or voltage-gated channels
97
Why doesnt the membrane potential not become more positive then 30mv?
Since Na+ channels quickly close and K+ channels open
98
The amplitdue (size) of action potentials is therefore...
All or none; if depolarization reaches the threshold, maximum potential change is reached
99
What is the threshold?
-55 mV; starts up again
100
Action potentials are sometimes called...
"Spike potentials" get stronger as the further you go right
101
How do action potentials work in non-myelinated axons?
The action potentials passes smoothly along the axon, and all parts are depolarized; Na+ moves along (3 Na+, 2K+)
102
What is saltatory conduction?
In myelinated axons, the action potential jumps btween non-insulated nodes of Ranvier, allows rapid movement of actionm potentials, and needs less energy to restore the membrane after action potential has been transmitted
103
What is the refractory period?
In myelinated or unmyelinated; helps ensure action potential only goes in one direction down the axon to its end
104
How do presynaptic and postsynaptic neurons work?
Presnyaptic at synapse and post at dendrites
105
Once action potentials reach the end of the axon...
They stimulate the next cell; axon to dendrite
106
In the CNS, the 2nd cell for the movement of the action potential is...
Also a neuron
107
In the PNS, the 2nd cell for the movement of the action potential can be...
Neuron, or an effector cells within a muscle of gland
108
What is the direction of synapses?
Presynpatic to postsynaptic
109
What do presynaptic neurons end in?
Terminal bouton
110
What does the postsynpatic terminal look like?
Tiny cleft about 10 nm in size
111
How does the synpase work?
1. Action potentials reach axon terminals
2. Voltage-gated Ca2+ channels open
3. Ca2+ binds to sensor protein in cytoplasm
4. Ca2+-protein complex stimulates fusion and exocytosis of neurotransmitter
112
What happens on the post synaptic side?
Neurotransmitter binds to its receptor on the dendrite
- Causes ion channels on postsynaptic dendrite membrane to open
- Note these gates are chemically regualted (not voltage-regulated as in axons IMPORTANT
- Stimulates cell to produce AP
113
How does one record membrane potentials
- Technique for recording the electrical current in a spinal neuron grown in cell culture
- Microelectrode: "patch clamp" recording technique
- This records voltage for a certain area of the cell membrane over time (electrical changes at one place)
114
What is myotonia?
Is a neuromuscular disorder that is characterized by delayed relaxation of skeletal muscle after voluntary contraction or electrical stimulation
115
How is myotonia caused?
- Can be caused by mutations in muscle Cl- channels
- Channel gates do not open properly
- Repolarization delayed, several APs fire instead of one
116
What does myotonia do in goats?
Produces a higher meat-to-bone ratio and a thicker musculatire with a more tender nature that has earned them a place on Slow Food Ark of Taste
117
What is the speed of impulse?
30-90 m/sec
118
Is everything we percieve in the past?
Yes
119
What do dendrites, cell body, and axons do?
Dendrites: collect electrical signals
Cell body: integrates incoming signals and generates outgoing signal to axon
Axon: passes electrical signals to dendrites of another cell or to an effector cell
120
How behind is your brain in interpreting information?
500 milliseconds
121
What is gray matter?
Contain neuron cell bodies and dendrites, is found in cortex (surface level) of the brain and deeper within the brain in aggregations known as nuclei
122
What does white matter consist of?
Axon tracts (myelin sheath make the white colour) that underlie the cortex, and surround the nuclei
123
What is the order of meninges of the brain?
PADS from inner to outer
Pia mater: clings to surface of brain/spinal cord, follows every fold
Arachnoid mater: web/spidery
Dura mater: tough mother two layers of skin
Skull
Scalp
124
What is the order of the meninges of the spinal cord?
PADS
125
In addition to the skull and meninges.. the brain is protected by cerebrospinal fluid which is...
Two fluid cushions that give some protection for the brain against head traumas (inner and outer fluid cushion)
126
What is the innner and outer cavity of the brain?
Outer cavity is the superior sagittal sinus (SSS) sits under dura mater (dura sinus talking about cars)
Inner cavity is subarachnoid space (SAS) space between arachnoid and pia mater
127
Which parts of the brain and spinal cord are filled with cerebrospinal fluid (CSF)?
Cavities (ventricles)
128
What is cerebrospinal fluid similar in composition to?
Blood plasma
129
What can CSF taps be used for?
Sample of CSF can be examined for signs of disease; bacteria, virus, inflammatory cells, abnormal products of degeneration as in MS
130
How many pairs of spinal nerves are there?
31
Cranial: 12 pairs
Cervical: 8 pairs
Thoracic: 12 pairs
Lumbar: 5 pairs
Sacral: 5 pairs
Coccygeal: 1 pair
Every one but cranial is spinal nerves
131
Each spinal nerve is a mixed nerve composed of...
Sensory and motor fibers, packed together; they seperate near the attachment of the nerve to the spinal cord
132
Where does the spinal cord extend from?
From the brain stem, to the pelvic region, endingding before the end of the verterbral column
- Nerves enter or leave the spinal cord in between the vertebrae
133
What do the interneurons do with the spinal cord?
Interneurons also communicate with one another along the length of the spinal cord; afferent sensory stimulus can be translated up or down the spinal cord by the interneurons
134
What is the link between the spinal cord and peripheral nervous system?
Reflexes; for example the "simple" withdrawal reflex response to a painful stimulus involves the contraction of several muscles, the relaxation of other muscles, and it may also involve responses that are intitated in the brain
135
What is an example between myotatic (stretch) reflex?
eg. knee-jerk reflex
136
With LMN damage reflex will be
Diminished
137
With UMN damage reflex will be...
Exaggerated
138
What are the three primary vesicles of the brain?
1. Prosencephalon (forebrain)
2. Mesencephalon (midbrain)
3. Rhombencephalon (hindbrain)
PMR
139
By what time are the three distinct swellings present?
Middle of 4th week after conception
140
What is a hemorrhagic stroke?
When blood leaks into brain tissue
141
What is ischemic stroke?
When clot stops blood supply to an area of the brain
142
What is telencephalon and diencephalon parts of the brain
T: cerebrum
D: thalamus+hypothalamus
143
What do midbrain and hindbrain do?
Contain many relay centers for sensory and motor pathways, and are important in the brain's control of skeletal movements
144
What is the cerebrum?
consists of left and right hemispheres, connected internally by the corpus callosum, preforms most of what are considered to be the higher functions of the brain. 5 regions
145
What does the frontal lobe do?
Motor control
146
What does the occipital lobe do?
Vision, and coordination of eye movement
147
What does parietal lobe do?
Perception of somatesthetic sensation- sensation arising from cutaeneous, muscle, tendon, and joint receptors (feel like from parents)
148
What does the temporal lobe do?
Interpretation and association of auditory and visual info
149
What is the insula?
Is a region buried deep within the lateral sulcus- division between the frontal and temporal lobes (front of brain)
150
What does the insula do?
Encodes memory, integrates sensory information with visceral responses. Recieves olfactory, gustatory, auditory, and somatosensory (mainly pain) information
151
What is cerebral lateralization?
Each of cerebral hemishphere recieves different input, but the two hemispheres communicate with each other via the corpus callosum
152
Why do soe people cut their corpus callosum?
Releaving symptoms as a way of alleviating their symptoms
153
Found that each hemisphere is good at certain tasks and poor at others; leads to the concept of...
Cerebral dominance, or cerebral lateralizattion or even handedness
154
What does damage to the right side of the brain cause? (right way)
Difficulty with spacial concepts, maps
155
Damage to the left side of the brain causes?
Severe speech problems, may leave the ability to sing unaffected
156
How much percent of people have the left side for language and analytical
90% (90% of right handed people rely on their brains left hemisphere for language skills)
157
About how much of left handed people rely of left hemisphere
70%; also rely on legt hemi for language; 30% half of them use right hemisphere for language and the other half use both hemi to process language
158
How does Prozac work?
Message is sent across the synaptic gap, message is recieved excess serotonin molecules are reabsorbed by sending neuron; Prozac partially blocks normal reuptake of the neurotransmitter serotonin; excess serotonin in synpase enhances its mood-llifting effect
159
Who was Kim Peek
No corpus callosum, rain man, remembers every page he reads, over 9000 books
160
What does the sheet of gray matter tissue that covers the cerebrum (and cerebellum) divided into L and R hemispheres do?
Important in memory and emotion
161
What does damage to the orbitofrontal area of the prefrontal cortex mean?
Impulsive behaviour verging on sociopathic
162
Who was Phineas Gage?
Railway worker accident, damage to cerebral cortex made him have personality changes
163
What makes up Diencephalon?
Thalamus and Epithalamus
164
What does the thalamus do?
Relay centre through which all sensory information (except smell) passes on the way to cerebrum
- Promotes alterness
- Causes arousal from sleep in response to any sufficiently strong sensory stimulus
165
What does epithalamus do?
Dorsal segment, contains the pineal gland which secrets melatoning (helps regulate circadian rhythms, hormone of darkness)
166
How much does the thalamus make up of the diencephalon?
4/5ths
167
Where is the hypothalamus located and what does it do?
Sits above optic chiasm, most inferior (lowest portion); site of master cirdadian clock-SCN (super chiasmatic nucleus); regulates daily processes, hunger, thirst, regulation of body temp, hormone secretion from pituitary, contributes to regulation of sleep and wake
168
What do the hindbrain and midbrain do?
Relay centers for sensory and motor pathways, and important for brains control of skeletal movements
169
What type of neurons are concentrated in the midbrain?
Cell bodies of dopaminergic neurons (dopamine releasing neurons)
170
What are the 2 systems of neurons for the midbrain?
1. Nigrostriatal dopamine system, involved in motor control
- Parkinsons disease caused by degeneration of the dopaminergic neurons in the substantia nigra
- Ex. Michael J Fox
2. Mesolimbic dopaine involced in emotional reward (mess emotions)
- Alcohol, cociane, and morphine promote the activity of these
- May also play a role in addiction (nicotine or other drugs)
- Overactivity in this region may contribute to schizo
171
When does schizo happen?
Late adolescence/early adulthood 40% of men and 23% of women condition came before 19
172
People with schizo may experience...
- hallucinations
- delusions
- disorganzied thinking and speech
- social withdrawal, poor dress and hygiene
- loss of motivation, judgment, emotional difficulty, unresponsiveness
- impaired social cognition, paranoia
- difficulties in memory, attention and processing
173
How big is the cerebellum?
2nd largest structure of the brain greater then 50 billion neurons, gray and white matter
174
What does the crebellum do?
Monitors and refines motor activity. recieves input from proprioreceptors (joint, tendon, muscle receptors) and signals from the motor areas of the cerebral cortex. participates in coordination of movement, fork ends here
175
Where is the medulla and what does it do?
Hindbrain; all fiber tracts giving communcation between spinal cord and brain muss pass through, required for regulation of breathing, CV responses (vital centers)
176
What is autism spectrum disorder?
Developmental disorder, manifests 3 months-3 years, affects speech, motor skill, social interaction
177
What is the Courchesne Theory of Overstimulation?
Autistic children seem antisocial since they shun external stimulation, since cerebellum cant take it, repetitive behaviour since calming
178
What is AS Asperger
Hyper focus, mild movement disorder, lack of social cues
179
PDD percasive developmental disorder
range of things
180
Temple grandin
Half of silicon valley has Aspergers
181
Following is a main division of the CNS?
a. afferent
b. efferent
c. somtic motor neurons
d. brain
e. parasympathetic nervous system
D. brain
182
Autonomic nervous system; only one of the following options below has dual sympathetic and parasympathetic innervation
a. adrenal medulla
b. arrector pili muscles
c. heart
d. sweat glands
e. all above
C. heart
183
Following are true except for
a. neuron is the minimal funct unit of nervous system
b. understanding stems from neuron doctrine of ramon y cajal
c. neurons conduct electrical signals
d. neurons release chemical signals
e. neurons transmit action potentials from dendrites to next cell
e
184
Choose incorrect
a. ciliary muscle and pupil of eye have parasympathetic innervation from cranial nerve III
b. heart has dual innervation from both parasympathetic and sympathetic
c. organs without dual innervation regulated by increases or decreases of the firing rate of parasympthathetic fibers
d. lung has parapsympathetic innervation from cranial nerve x
e. arrector pili msucles in the skin lack dual innervation
c!
185
How much gas do we produce?
1/2 litre per day, spread out over 14-25 incidents
186
How long does it take one to digest food?
- about 6-8 through stomach, large and small intestine
- total transit around 53 hr (most in large)
- women 47 hr
- men 33 hr
187
What is the difference between digestion and metabolism?
Digestion:
- Breakdown of ingested food
- Absorption of nutrients into blood
- Concentration and removal of waste products
Metabolism
- Production of cellular energy (ATP)
- Regulation of cellular activities
188
What are the two main functional groups of organs in the digestive system?
Alimentary canal
- Continuous hollow tube
Accessory Digestive Organs
189
What are the structures of the alimentary canal?
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small intestine
- Large intestine
- Anus
190
What covers the tongue?
Backward facing projections called filiform papillae, which sense pressure
191
A species of frog can hear with its...
Mouth
192
What are all the organs of the tube (alimentary)
Oral cavity, esophagus, stomach, duodenum, large intestine (colon), small intestine, rectum, anus
193
What are all the accessory organs?
Salivary glands, liver, gall bladder, pancreas
194
What are the glands in the head?
Paratoid (near the ear), submandibular gland (under mandible), sublingual gland (under tongue)
195
What are the functions of the salivary glands?
- Lubrication/binding
- Solubilization of dry food (liquify)
- Oral hygiene- flushes away debris
- Begins starch digestion (salivary amylases)
- Alkaline buffering (right pH for food to be digested)
- Evaporative cooling (more important in dogs)
196
What does mastification mean?
Chewing food
197
What do each of the different types of teeth do?
Incisors: rip, cut
Canines: tear, pierce
Premolars: grind, shear
Molars: grind
198
Are teeth the hardest structures in the body?
Yes
199
How many baby teeth do we have?
20
200
How many adult teeth do we have? How much with wisdom teeth removed?
32; 28 removed
201
What is deglutition? and what does it consist of? How many muscles does it include?
Swallowing; oral, pharyngeal, esophageal; requires 25 pairs of muscles in the mouth, pharynx, larnyx, upper esophogus
202
What are the muscles that are innervated by somatic motor nerves?
Mouth, pharynx, upper esophagus
203
What are the mucles that are innervated by autonomic neurons?
Middle and lower esophagus
204
What does the esophagus connect? and how long is it?
Connectes pharynx to stomach; muscular tube about 25 cm long
205
What is peristalsis?
Food moves by a wave-like muscular contraction
206
Where does peristalsis take place?
In the esophagus; peristaltic contraction and movement of a bolus into the stomach
207
Where does the esophagus run from?
- Runs from pharynx to stomach
- Passes through diaphragm
- Mobilizes food by peristalsis
208
Does peristalsis continue in the stomach?
Yes; carries food from stomach through the pylorus into the duodenum which is the first part of the small bowel
209
What do the smooth muscle layers in the wall of the stomach do; what direction do they run in?
Run in oblique direction; muscles act to mix and mechanically break up food in the stomach
210
What are the types of muscles in the stomach? What advantage does this provide?
Circular (around), longitudal (longest ones), and oblique (on an angle); provide complex motility (able to move independently)
211
What does the mucosal region of the stomach contain?
Gastric pits and gastric glands
212
What are gastric pits and gastric glands?
Gastric pits: openings of the gastric glands (openings)
Glands: have several types of cells (on side) (mucous cells, chief cells, parietal cells)
213
What do mucous cells do?
Secrete mucus
214
What do parietal cells do?
Secrete HCl (helps to keep environment for enzymes to work), intrinsic factor (B-12 essential for life)
215
What do chief (zymogenic) cells do?
Secrete pepsinogen (protein that helps protien digestion in the stomach)
216
Why doesnt the stomach digest itself?
Has mucous cells that cover the stomach
217
What do erosions in the mucosa in the stomach cause?
Peptic ulcers (ie the stomach digests itself) caused by helicobacter pylori
218
The bacteria helicobacter pylori affects how many of adults worldwide?
About 50%, bacteria are responsible for the ulcers rather than spicy food
219
What do pepsinogen/HCl do?
In the presenceof HCl, the active enzyme pepsinogen is activated to the pepsin form, which can digest proteins into smaller polypeptides
220
What are the regions of the small intestine?
Duodenum
-First 25 cm
- Mucous secretion, recieves pancreatic secretions and bile from liver
Jejunum
- 1m in length
- Numerous folds and villi
Ileum
- Last 2m
- Fewer folds/villi than jejunum
- Absorbs primarily bile salts, water, electrolytes
- Contains Peyer's patches (aggregates of lymph nodes is the immune system of the gut)
- Empties into large intestine via ilieocecal valve
DJI
221
How are microvilli formed?
By foldings at the apical surface (top of epithelial cell) of each epithelial cell membrane
222
What are villi covered with?
Columnar epithelial cells
223
What do goblet cells do and where are they found?
Secrete mucous; and found on villi
224
Where do the epithelial cells at the tip of the villi go?
Sloughed off and replaced by new cells coming from tjhe intestinal crypts (crypts of Liberkuhn)
225
What do paneth cells do?
At the base of the crypts secrete antibacterial molecules (lysozyme, antimicrobial peptides) to protect the intestine from inflammation PANETH PROTECTS
226
Are microvili the same as villi?
NO!
227
What are some types of enzymes that are brush broder enzymes in the small intestine?
Sucrase, maltase, lactase, aminopeptidase, enterkinase, Ca2+, Mg2+, ATPase, alkaline phosphatase
228
Can changing your meal schedule be effective in fighting body fat?
Eating only during a much smaller window of time than people are typically used to may help with weight loss
229
What happened in the study of mice who had food available 24 hours and one for only 8 hours?
Mouse with food for 24 hours had 38% more body fat then the mout who had food for only 8 hours of the day; mouse eating 24hr per day had 4x more body fat even though they ate the same number of calories
230
What is a main difference between the small and large intestine?
Large intestine is smoother
231
What is one factor of the colon (large intestine)?
- Bacterial colony is made up of many species of bacteria and plays an essential role in digestive processes
- Good bacteria out competes pathogenic bacteria
- When pathogenic bacteria take over the colon reacts by eliminating colon content and sloughing off the colon epithelium-diarrhea
232
What is the appendix?
Is a small component of the colon; appendix is now though to be a reservoir of "good bacteria" that can re-colonize the colon following diarrhea, and expulsion of the colon content; the appendix does not function in digestion, but like the tonsil it contains lymph vessels
233
What is apendicitis?
inflammation, causes pain in the lower right of the abdomen, ruptured appendix can cause inflammation in the peritoneal cavity-peritonitis
234
How much intestinal microbiota are in the body?
10x more than number of human cells in the body; commensal and mutualism the bacteria benefit and so do we
235
Do we need different bacterial confirmiations for differing foods
Yes
236
When does intestinal microbiota originate?
At birth
237
Is gut microbiota affected by what you eat?
Yes, beginning at birth, gut microbrial colonies, known as gut microbiome, start forming
238
Does gut bacteria regulate happiness in humans?
Absense of bacteria during early life affected serotonin concentrations in the brain; serotonin alters stress, anxiety, depression
239
What does dysbiotic micrboiota cause by?
Cystic fibrosis, autism, obesity
240
What are the accessory organs of digestion?
Pancreas, liver, gallbladder
241
What is the liver made up of?
- Made up of hepatic cells lining large capillaries called sinusoids
- Sinusoids also lined by endothelial cells
- Sinusoids also contain Kupffer cells (phagocytes)
- Has amazing regenerative capabilities- if 2/3 of liver is removed, remaining tissue will regenrate to original mass in 1 week LIVE (wants to live)
242
What are the two liver blood inputs?
- Portal vein (coming from intestines, major source of blood supply to liver)
- Hepatic artery (blood from heart to liver)
243
What is the endocrine function?
Enzymes and hormones of the liver do their thing, and output gets sent into the hepatic vein and that goes on back to the heart, so the nutrients loaded into there can get pumped through the whole body
244
What are the 2 exocrine regions?
Right and left hepatic ducts that come out of liver, which makes bile. Bile is stored in gallbladder. The R/L hepatic ducts eet up with the cystic duct from the gall bladder which stores bile, and together they form the common bile duct which goes into the intestines
245
How is bile made?
Derivative of the heme group (minus the iron) converted into bilirubin, carried in the blood on albumin proteins, taken up by the liver, mixed with glucoronic acid, and now is water soluble and can be made into bile, to intestine, converted by bacteria into urobilinogen, and removed in feces, some urobilnogen can re-enter circulation and be excreted by kidneys. Fe2+ gets recycled to bone marrow
246
What is the gallbladder?
Sac-like organ attached to the inferior surface of the liver; stores and concentrates bile from the liver
247
What are a common complication with the gallbladder?
Gallstones; they are mineral deposits that produce painful symptoms by obstructing the bile ducts; removed by surgery, sometimes oral ingestion of bile acids, or fragmentation by high energy shock waves
248
How mant different digestive enzymes do pancreatic juices have?
Contains 20 different digestive enzymes
Amylase-digests strach
Trypsin-digests proteins
Lipase- digests triglycerides
249
What does digestion require in regards to pancreas?
Requires pancreatic enzymes plus brush border enzymes; inactive form of pancreatic enzyme trypsin is activated by brush border enzymes; trypsin is a protease that can activate other pancreatic enzymes; trypsin activates other enzymes
250
What is the endocrine portion of the pancreas?
Pancreatic islet (or Langerhans)
251
What is the exocrine portion?
Pancreatic acini
252
What does endocrine gland do?
Makes hormones (endo in): insulin, glucagon, somatostatin
253
How much of carbs are used by the body?
50% of our calories
254
How much of proteins are used by the body? Lipids?
11-14%; most of the rest
255
Proteins, carbs, lipids cholesterol which one can go across by itself?
Cholesterol
256
What is motility?
Moves thorough the digestive tract; breaks mechanically
257
What is secretion?
Release of enzymes, hormones, and other substances that help the body to digest food
258
What is digestion?
Breaking down of food into components small enough to cross the plasma membrane
259
What is absorption?
Transfer of single nutrient molecules to the blood or lymph
260
Physiology wise humans teeth are similar to?
Frugivore
261
How many stomachs do ruminants have and what are they?
4, reticulum, rumen, omasum, abomasum, more efficient! most herbivores are ruminants, first microbrial then enzymatic (microbes get degraded by enzymes)
262
What are simple stomach animals and how does that work?
Horse and donkeys; first enzymatic then microbial, body of bacteria not absorbed, goes stomach, then small intestines, then small and large colon, cecum
263
What are the two types of digestion?
Enzymatic: carbs (amylase, maltase, lactase), proteins (pepsin, trypsin, peptidase), fats (lipase)
Microbrial: fermentation
264
Digestion in animals takes which type of digestion?
Enzymatic
265
Digestion in herbivores, omnivroes and frugivorous is...
Microbial and enzymatic
266
What are the major groups of carbs?
Monosacchardies (glucose, fructose, galactose)
Disaccharides (sucrose, maltose, lactose)
Polysaccharides (starches; complex carbs)
267
Most carbs are ingested as...
Starches
268
The most commonly ingested sugar is?
Sucorse (table sugar) and lactose (from milk)
269
How do carbs get digested?
Starch (polysaccharide) (with amylases break down into)
- Disacchardies (with brush border enzymes such as dextrinase, glucoamylase, lactase, maltase, sucrase) break that into monosacchardies (simple sugars)
270
How does digestion of carbs in the mouth and stomach work?
- Chewing mixes food with salivary secretions containing ptyalin (an alpha amylase)
- Ptyalin hydrolyzes starches into maltose and other small glucose polymers
- Up to 30-40% of the starches can be hydrolyzed to maltose in the mouth and stomach
271
What happens because people dont chew their food for very long?
Salivary amylase is inactivated by stomach pH, and rest of complex carbs get digested from pancreatic amylase
272
How does digestion by pancreatic amylase work?
- Pancreatic secretions contain a large quantity of amylase
- Pancreatic amylase is more potent than salivary
- Within 30 mins, almost all carbs are hydrolyzed to maltose (and other small glucose polymers) in the duodenum and jejunum (small intestine)
273
How are disaccharide sugars digested?
Lactose, sucrose, maltose are digested by brush border enzymes, lactase, sucrase, and maltase
- Lactase breaks into galactose and glucose
- Maltase breaks into 2 molecules of glucose
- Sucrase breaks into glucose and fructose
- Monosaccharides formed are galatocse, glucose, fructose; internalized by absorptive cell and diffuse out into caps of the intestinal villi
274
What is the final product of carbohydrate hydrolysis?
Monosaccharides
275
Are monosaccharides water soluble?
Water soluble and are absorbed immediately into blood stream
276
What are the typical breakdown products of carbs??
80% glucose
10% galactose
10% fructose
277
What happens with blood leaving the villi?
Blood leaving the villi or small intestine drain into blood bessels that lead right to liver (hepatic portal); blood leaving the villi is rich in nurients; is thhis nutrient load were allowed to enter the general circulation blood viscosity would be increased with possible adverse affects on blood pressure
278
What is the first pass effect?
When the blood passes through the blood vessles of the liver, much of the nutrient load is removed
279
What is the role of glucose and what does the body do if it has excess?
Essential nutrient for energy production by many cells; gluocse is excess can be converted into polysacchardie glycogen, and stored in lover and muscle
280
What happens to glycogen later?
Glycogen is broken back down to simple sugars (or liver can make glucose from non carb substances like fats and proteins)
Goes from glucose monomers to glycogen polymer (storage)
281
What are pancreas role?
1. Endocrine gland: making hormones (insulin, glucagon, somatostatin, etc)
2. Digestive organ: secreting digestive enzymes destine for the small intestine
- Enzymes help digest chyme, carbs, proteins, lipids
282
What helpd to bring glucose into cells?
Insulin, gluocse in bloodstream, insulin released by pancreas, insulin binds to cell surface receptors, triggers gluocse uptake by facilitated diffusion
283
What does high glycemic index mean?
Your blood sugars rise quickly after a meal
284
What is a low gi, medium and high
low less then 55, medium from 55-69, high greater then 70
285
What is GU
Energy drink, 100 calories from complex sugars (+AA, electrolytes, caffeine)
286
What happenned to mice on the high GI diet vs those on the low GI diet?
High-GI diet had 2x more body fat then those on the low GI diet
287
What happens to those with high glycemic index?
Sugar crashes
288
Which foods are best for those with diabetes?
Foods that have low GI to match with the insulin, less blood sugar roller coaster
289
What are examples of low carb diets?
Atkins, Keto, Bernstein, NSNG (no sugar no grains)
290
What helps those with diabetes?
GLP1 receptor agonsists with type 2 diabetes
291
What GLP-1
Glucagon like peptide-1 increases insulin, decreases glucagon, tells brain to lower appetite so no excess glucose, and stomach slows down feeling full
292
What are the potential benefits of GLP-1?
- Type 2 diatbetes
- Weight loss
- Reducing CV risk
- Better insulin and glucose control
293
What are the downsides and risks of GLP-1?
- GI side effects-lifelong
- Thyroid tumours
- Pancreatitis
- Hypoglycemia
294
Where do we get cholesterol from?
Meat, esp organ meats, yolks, butter, oils, cream
295
How is cholesterol abosorbed?
Without digestion
296
Where is most of our cholesterol produced?
85% the liver, and 15% from diet
297
How is cholesterol transported?
With lipoproteins
298
Why is cholesterol important?
Major component of cell membranes, and base substrate for synthesis of steroid hormones
299
What are the major lipid groups in our diet?
- Trigylcerides
- Phospholipids
- Sterols (such as cholesterol)
Know how to draw first two
300
Where does most of fat get digested?
- Trigylcerides are digested by lingual lipase swallowed with saliva
- Very small amount of fat digestion occurs in the stomach, less then 10%
301
What problems do lipids have that carbs and proteins dont have?
Since lipids are not water soluble, problems with digestion, so enzymes cant get to them
302
What helps the digestion of lipids?
Bile salts help lipid digestion by emulsifying lipids- broken into small droplets; has the effect of greatly enhancing the access of the lipases to lipid molecules
303
What enzymes digest trigylcerides and phospholipids? Where are they present?
Lipases; present in pancreatic juices, thus lipid digestion can only occur in the small intestine (following emulsification by bile salts)
304
What is the most important enzyme responsible for digesting triglycerides?
Pancreatic lipase; pancreatice juice contains an enormous amount of lipase- within 1 minute there is enough pancreatic lipase secreted to digest all of the triglyceride it reaches
305
What does pancreatic lipase splits trigylcerides into?
Free fatty acids and monogylcerides (glycerol and fatty acid)
306
What are the steps of chemical digesion in lipids?
1. Emulsification of fat droplets by bile salts
2. Hydrolysis of trigylcerides in fat droplets into fatty acid and monoglycerides
3. Dissolving of fatty acids and monoglycerides into micelles to produce "mixed micelles"
307
Where is pancreatic lipase active?
Small intestine
308
What are the products of triglyceride and phosholipid digestion (by lipase) are...
Monoglycerides, fatty acids and glycerol; these diffuse into absorptive cells
309
Where do droplets of triglyceride leave the cells by?
Exocytosis; enter the lacteals of the villi
310
Where are chylomicrons secreted?
Into central lacteals of the intestinal villi, passing via the lympathic system until they reach the blood through the thoracic duct
311
What do chylomicrons add to help it bind to capillariesin the target muscles and adipose tissue?
ApoE protein
312
How does target tissues release the fatty acids, used by the skeletal muscles for energy, adipose for synthesis of stored fat
Lipoprotein lipase
313
What happens after the trigylcerides are broken up?
Depleted chylomicron particle back through circulation to the liver
314
What are proteins?
Polymers of amino acids
315
What are proteins digested by that shortens them a bit?
Proteases produces large polypetides (shorter chains of amino acids)
316
What digests large polypeptides?
Peptidases produces smaller amino acid chains (peptides)
317
What digests peptides into amino acids?
Peptisases (more so brush border peptisases)
318
Where is protease located?
Pepsin (stomach)
319
At what pH does pepsin function at?
pH 2-3, inhibited at pH greater then 5
320
What enzyme digests collagen?
Pepsin, collagen is a main component of connective tissue found in meats
- In order for meat digestion to occur, collagen must first be broken down by pepsin
321
Pancreatic secretions contain a number of...
Proteolytic enzymes that can act in the duodenum and upper jejunum
322
What are examples of proteolytic enzymes?
- Trypsin
- Chymotrypsin
- Carboxypeptidase
- Proelastase
323
What are enterocytes?
Contain other peptidases that are specific for linkages between amino acids
324
What do endopeptidases and example?
Like trypsin; cleave internal bonds
325
What are exopeptidases?
Cleave off the ends
326
Are about 99% of final protein product single amino acids that pass into blood stream?
Yes
327
How are amino acids transported into absorptive cells?
By transport proteins (carrier-mediated transport)
328
How are peptides digested?
By brush border peptidases; AAs formed are transported by a transporter associated with the enzyme into the absorptive cells
329
What do transport proteins carry the AAs to?
Out of absorptive cells to capillaries of the villi
330
Can amino acids be stored?
Cannot; except as components of cell protein
331
What do AAs in excess of immediate needs are..
Metabolized by liver cells
332
How are amino acids removed?
Nitrogen (amine) unit of AA used to make urea; remaining part is used to make lipid, urea is excreted as part of urine
333
How are Ca2+ absorbed?
- Active absoprtion in blood
- Controlled stringently
334
What does parathyroid hormone do?
Activates Vit. D which enhances calcium absoprtion
335
What is iron important for?
- Formation of Hb, for RBCs carry oxygen
336
How are K+, Mg2+, phospates absorbed?
Direct absoprtion through intestinal mucosa
337
Where does vitamin absorption occur?
Diffusion in the jejunum and ileum
338
How are fat-soluble vitamins absorbed?
Dietary lipids (vitamins A, E, D, K)
339
What are some water soluble vitamins and how do they get into blood?
B1 thiamine, B2 riboflavin, B3 niacin, B6 pyridoxine, panthothenic acid, biotin, folic acid, B12, Vit C ascorbic acid) diffuse into blood except for vitamin B12, b12 combines with intrinsic factor produced by stomach, which the intestine abosrbs by endocytosis, water soluble vitamins pass into urine when their concnetration in plasma exceeds the renal capacity for reabsoprtion
340
Which system contains the most blood?
Venous system; functions as a reservoir from which more blood can be added to the circulation under appropriate conditions (such as excercise)
341
What is the difference between veins and arteries?
Veins: less thick, artieres have more elastic hold shape since deal with more pressure from heart taking the oxygenated blood to whole body
342
Why do veins carry most of the blood?
Veins are able to expand as they accumulate additional amounts of blood
343
What is the average pressure in veins vs arteries?
2mmHg (mercury); arterial 100mmHg
344
What does the body do to help return blood to the heart?
Venous pressure is too low to return blood back to the heart; to help veins of the lower limbs, veins pass between sketal muscle groups that provide contractions to help move blood back (called skeletal muscle pump)
345
What helps venous blood from the abdominal and thoracic regions?
Act of breathing and contraction of the diaphragm and pressure in the abdomen from breathing squeezes the veins and helps the venous blood return to the heart
346
What types of fibers are in the aorta and other larger arteries?
Numerous layers of elastin fibers between the smooth muscle cells of the tunica media
347
What happens when blood pressure rises?
Elastic arteries expand as a result of ventricles contraction; recoil like a stretched rubber band when the blood pressure falls during relaxation ofthe ventricles
348
What systolic or diastolic is when the elastic recoil drives blood during the...
Diastolic; when the heart is resting and not providing pressure
349
Which arteries diameter only changes slightly?
Small arteries and arterioles
350
How many capillaries are in the body?
Over 40 billion capillaries; number is so great that any cell in the body is 60-80 (micrometer) away from blood capillary
351
Which increases blood flow? Vasocontrcition or vasodilation?
Vasodilation decreases blood flow to capillary bed; vasodilation increases it
352
What is a main difference between artieral and venule tissues vs capillary walls?
Capillaries are made of just one cell layer, lack smooth muscle and connective tissue; makes it easier to exchange materials between blood and tissues
353
Where is fluid reabsorbed?
In the venous end of the capillary
354
Where does the nasal cavity lead into?
Pharynx (throat); which is a muscular passage connecting the nasal cavity with the larynx
355
What does the larynx do?
Air is diverted toward the lungs and food is diverted to the esophagus to the stomach; also contains the vocal "cords"; despite their name; these so-called cords are folds in the lining tissue of the larynx
356
What happens in capillary beds?
Gas exchange occurs
357
What is a pulmonary artery?
Artery but low O2; artery since travelling away from heart
358
What is a pulmonary vein?
Vein but highly oxygenated; vein since travelling to heart
359
What are the physical properties of the lungs?
1. Inspiration and compliance; must be able to expanf when stretched; dv/dp
2. Expiration and elasticity; lungs are normally attached to chest wall; pleural fluid holds the two pleural membranes together
3. Surface Tension
4. Lung volume and capacities
360
What do the lungs need for inspiration to occur?
Lungs must be able to expand when stretched; must have high complicance (distensibility, stretchability)
361
What is lung compliance?
Change in lung volume per change is transpulmonary pressure dv/dp, so at any pressure, there will be greater or lesser expansion, depneding on compliance
362
For expiration to occur what must you need?
For lungs to get smaller wen tension is released, must have elasticity; elasticity is the tendency of a structure to return to its intial size after being distended; since there is a high content of elastin proteins, lungs are very elastic and resist distension. Lungs are normally stuck to chest wall, so always in a state of elastic tension, tension increases during inspiration when the lungs are stretched, and reduced by elastic recoil during expiration
363
Can the lungs inflate if they are not attached to the wall cavity?
No; they cannot inflate if they are attached to the inner wall of the chest cavity
364
What are pleural membranes?
Attachment of the outer lung surface to the inner surface of the chest cavity is made with membranes called pleural membranes (sandwhiches the wall and the lung)
365
What do the Plural Mebranes Produce?
Produce a mucous rich lubricating fluid (pleural fluid) into the space between the two membranes called the pleural space (but isnt really a space since the membranes lie close to one another
366
What is the glue that holds together the inner wall of the thoracic cavity and the lungs?
Pleural fluid
367
What is surface tension exerted by?
Fluid in the alveoli; fluid contains a surfactant, mixture of phospholipids and hydrophobic surfactant proteins, secreted into the alveoli by type II alveolar cells
368
What does surfactant do?
Lowers the surface tension in the alveoli, which prevents the alveoli from collapsing during expiration
369
What causes respiratory distress syndrome?
Surfactant is produced late in fetal life; premature babies are somethimes born with lungs that lack sufficient surfactant and their alveoli are collapsed as a result
370
What is tidal volume?
Volume of gas inspired or expired in an unforced respiratory cycle (about 500m/s)
371
Inspiratory reserve?
Max volume of gas that can be inspired during forced breathing in adiition to tidal volume
372
Expiratory reserve?
Max volume of gas that can be expired during forced breathing in additoin to tidal volume
373
What is residual volume?
Volume of gas remaining in lungs after max expiration
374
Total lung capacity?
Total amount of gas in the lungs after a max inspiration
375
Vital capacity?
Max amount of gas expired after a max inhalation
376
Inspiratory capacity?
Max amount of gas that can be inspired after a normal tidal expiration
377
Functional residual capacity?
Amount of gas remiaining in the lungs after a nomral tidal expiration
378
What is anatomical dead space or where no gas exchange occurs?
Nose, mouth, larynx, trachea, bronchi, bronchioles about 150 m/s
379
What is the perentage of fresh air reaching the alveoli if... the anatomical dead space is 150m/s and tidal volume is 500m/s
150 dead space 500-150=350
350/500x100%=70%
380
What does hemoglobin contain?
Contains iron; present in cytoplasm of RBCs
381
Why is hemoglobin important?
It chemically combines with O2, but also releases gas when cells need it; hemoglobin acts as a O2 shuttle from lungs to body tissues
382
What are Co2 levels like in the lungs?
Co2 diffuses from the blood to the avleoli and blood Co2 levels are low- reduces the acidity of blood in the lungs (eg higher pH)
383
What are Co2 levels like in the tissues?
Blood co2 levels are high since the cells produce the gas as an excretory product, and O2 levels are low since it is being used by the cells- this increases the acidity of blood in the tissues (eg lower pH)
384
When does hemoglobin form oxyhemoglobin
Low acidity/higher pH in the lungs
385
When is O2 released from oxyhemoglobin?
High acidity/lower pH in the tissues
386
Hemoglobin what is another role for it?
Acts as a CO2 shuttle from body tissues to lungs
387
Why does oxyhemoglobin formation occur in the lungs?
Because blood Co2 levels in the lungs are low
388
Is CO2 constantly made?
Yes, by product of metabolism constant movement by diffusion, from body cells to blood plasms
389
Does CO2 have low solubility?
Yes so only very little can be carried in simple solution
390
What happens to CO2?
As it diffuses from body cells into plasma; it diffuses into RBCs and is converted into bicarbonate ion (HCO3-) by the enzyme, carbonic anhydrase, that is present in the RBCs
2. Small amount of CO2 is also attached to HB; called carbamino compounds
391
What is the equation for CO2 conversion to bicarbonate in RBCs
CO2+H2O->H2CO3->H+HCO3- (spontaneous) general body tissues, constant production
392
Which eway does the equation move in lungs?
Co2 is being lost to the alveolar air sacks and moves from right to left; since the HCO3- is entering the lungs
393
Getting rid of CO2 makes the o2 uptake more efficient?
YES
394
Which ventricle prefrmos more work?
LV much greater (by a factor of 5-7) that perfromed by RV, LV wall is thicker (8-10 mm) vs the RV wall (2-3mm)
395
The AV valve between the RA and RV has how many flaps and what it is called?
3; tricuspid valve
396
What is the AV valve between the LA and LV called? and How many valves?
2 flaps; bicuspid valve or sometimes called the mitral valve; atrioventircal valves (goes into ventricle)
397
What are the valves called that are located at the pulmonary atery and aorta?
One-way semilunar valves
398
How much blood does the contraction of ventricles in systole eject?
About 2/3 of blood they have, called the stroke volume, leaving 1/3 inital amount in the ventricles as the end-systolic volue
399
What is stroke volume?
Amount of blood coming from the ventricle in 1 heart beat
400
What is cardiac output?
CO=HRxstroke volume
401
At an average cardiac rate of 75bpm each cycle lasts how long?
0.8 seconds, 0.5 spent in diastole, 0.3 in systole
402
What are the 3 regions of the heart that can facilitate or generate action potentials?
1. Sinoatrial node (SA node) functions are pacemaker, located in RA, near the opening of the superior vena cava
- Vagus nerve innervates the SA node, can adjust HR
2. AV Node
3. Purkinje fibers
403
How does the elctrical acitivty of the heart work?
1. Impulse starts at SA node
2. Goes to AV node
3. Continues through AV bundle (or bundle of His)
Descends down the intraventricular septum, divides right and left with Purkinje fibers in the ventricle wall
- Spreads from endocardium to epicardium cuasing both ventricles to contract simultaneously
404
Where does impulse of heart start?
Impulse starts at SA node
- spreads quickly (0.8-1.0 m/s)
Goes to AV node
- conduction rate slows (0.03 to 0.05 m/s)
Continues through AV bundle (or bundle of His)
- Conduction rate increases
Descends down the intraventricular septum, divdies left and right with Purkinje fibers in the ventircle wall
- Conduction rate peaks at 5m/sec
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What is the AV node?
Located at the posterior septal wall of the right atrium, conduction rate slows, allowing atria to contract and fill ventircles
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What is an ECG or EKG?
ECG is not the recording of a single action potential,but it does result from the production and condujction of action potetnaisl in the heart called electrocardiogram
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What is P; QRS and T?
P: atrial depolarize
QRS: ventricular depolarization
T: ventricular repolarization (diastole)
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What does Coronary Artery Disease cause?
Contributor to coronary heart disease, which leads to heart failure, no cure for heart failure
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What is coronary artery disease?
Occurs when you have plaque build-up in one or more of the 3 cornary arteries; if it restricts blood floe to heart causes chest pain or angina
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What happens to S-T segment as a result of myocardial ischemia (heart attack)?
Ischemic is a lot longer; signal is heading out to centricles, they are relaxing heading to diadstole, but lie problem because of infarct region
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What is normal sinus rhythym?
60-100 bpm
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What is bradycardia?
less then 60 bpm
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What is tachycardia?
greater then 100
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What is ventricular fibrillation?
chaotic rhythm and rate
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What are some features of myocardial cells?
Myocardial cells; striated; contain actin filaments and myosin filaments arrangewd in the form of sarcomeres; contract via a sliding mechanism
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How are myocytes connected?
Connected via gap junctions, at the ends of each myocardial cell, which allows electrical impulses to be conducted cell to cell (so heart cells beat in synchrony); gap junctions stain as "intercalataed disks
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What are the 2 major organelles for myocytes?
Mitochondria for energy, and sarcoplasmic reticulum (SR) for calcium (ca2+ handling)
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Where do cardiac action potentials orginate?
In the Sa-node (pacemaker)
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What does the contraction of the heart follow?
Ca+-induced Ca2+ release; Ca2+ enters myocyte cytoplasm through voltage gated channels, then stimulates opening of the Ca2+ release channels in the sarcoplasmic reticululum SR; so ca2+ from the voltage channels serves a s a messenger for Ca2+ release channels; in order for the heart muscles to relax, the Ca2 in the cytoplasm must be pumped into the SR
420
How does excitation-contraction coupling in cardiac muscle work? Voltage gated calcium channels open
1. Ca2+ diffuses from ECF to cytoplasm
2. Ca2+ release channels on SR open
3. Ca2+ released from SR binds to sarcomere, stimulates contraction
4. Ca2+ ATPase pumps calcium into SR
5. Myocardial cell relaxes
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How thick or thin are actin and myosin?
Actin: thin
Myosin: thick filaments
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What are called myofibrils?
Cells are arranged into long, rod-shaped organelles, have a striated patten of alternating light and dark bands and z-disks
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What are the z-disks?
Proteins that act as anchors for thin protein filaments; these consist of a protein called actin
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What is each myofibril seperated into?
Seperated into structures called "z-disks" the section of the fibre betqeen the Z-disks sarcomere
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The light bands are called, dark bands are called, where do the z-disks lie, what is in the centre of the A band
Light are called I: actin
Dark bands called A: myosin
Z disks lie in the middle of I
Center of A band is narrow light band called H zon
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What are thick filaments made up of?
Made up of rod-shaped proteins, have angular head at one end; contraction of muscle is cuased by swivelling of the head
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What is tropmyosin attached to? Troponin consists of?
Tropomyosin attaches to actin; troponin complex of 3 subunits is attached to tropomyosin
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Explain what happens with myosin when ATP comes
Myosin head has an actin binding site and ATP-binding site, when ATP hydorpyxzed tob ADP, myosin head allows Ca2+ to attach to troponin causing movement exposing binding site on the actin, myosin corss bridges can attach to actin and undergo power stroke
Relaxed muscle tropomyosin blocks the sites, troponin is like a switch
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WHat are thr 3 categories to skeletal muscle contraction?
Speed, strength, endurance
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What are the 3 differences between cardiac and skeletal muscle contraction?
Skeletal Muscles require external stimulation by somatic motor nerves, skeletal muscles are long and fibrous; have direct excitation contraction coupling between transverse tubles and SR
Cardiac muscle: produces action potentials automatically (SA node), myocardial cells are short, branched and in, and interconnected; cells are tubular and aadjoined to myocardial cells by electectrical synoases (gap junctions), cardiac cells the voltage gated Ca+ channels in the plasms mebrance and the Ca2+ release channels in the SR do not direcrtly interact, instead is Ca2+ induced Ca2+ release
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Why dont cats get coronary heart disease?
Do have congetial heart problems, congestive heart fialure, treatments in huans are relventa tot animals, insufficient taurine in diet (cats) heart failure
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What condition are Doberman pinchers more liley to be diagnosed with?
Makes it harder for blood to pump out to body, muscle fibers have stretched heart chambers enlarge; dilated cardiomyopathy
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