Homeostasis Flashcards
(225 cards)
1
Q
What is the nervous system responsible for?
A
receiving information about the external and internal environment, processing the information and generating a response
2
Q
What are the 3 parts of the nervous system?
A
the brain, spinal cord and nerves
3
Q
What are the 3 principle functions of the nervous sysetm?
A
sensory input, integration and motor output
4
Q
What is sensory input?
A
receiving information about changes in the environment from sensory neurons
5
Q
What is integration?
A
interpreting the information in the brain or spinal cord by interneurons
6
Q
What is motor output?
A
coordinating a response from muscles or glands by motor neurons
7
Q
What are the 2 major divisions of the nervous system?
A
The central nervous system and the peripheral nervous system
8
Q
What does the CNS consist of?
A
the brain and spinal cord
9
Q
What does the CNS do?
A
takes in information from sensory receptors, processes it, coordinates an appropriate response by effectors
10
Q
What does the CNS contain?
A
mainly interneurons
11
Q
What is the PNS made of?
A
sensory organs, effectors and nerves
12
Q
What does the PNS do?
A
relays signals to the CNS from sensory receptors, motor nerves relay signals from the CNS to effectors
13
Q
What does the PNS consist of?
A
sensory and motor neurons
14
Q
What are the 2 types of nervous system cells?
A
neurons and glial cells
15
Q
What do neurons do and how many are there?
A
receive and transmit nerve impulses throughout the nervous system, 3 kinds
16
Q
What do glial cells do and how many types are there?
A
they provide support for neurons and there are 5 main types
17
Q
What is a neuron?
A
the structural and functional unit of the nervous system
18
Q
How many types of structural types of neurons are there and what are they?
A
3, multipolar neurons, bipolar neurons and pseudounipolar neurons
19
Q
What are multipolar neurons?
A
a neuron with many dendrites, one axon and a cell body near the dendrites
20
Q
What are bipolar neurons?
A
a neuron with one dendrite, one axon and a cell body in the middle
21
Q
What is a pseudounipolar neuron?
A
a neuron with a cell body with 1 extension split into 2 axons with dendrites at the ends
22
Q
What are the functional neurons and how many are there?
A
3, sensory neurons, interneurons and motor neurons
23
Q
What do sensory neurons do?
A
they transmit signals from sensory receptors to the CNS
24
Q
What do interneurons do?
A
they transmit signals between sensory and motor neurons
25
What do motor neurons do?
they transmit signals from the CNS to muscles and glands
26
What do interneurons allow?
they allow the nervous system to integrate information and coordinate a response
27
What is a reflex?
a rapid, automatic response that bypasses the brain
28
What is a nerve?
a cable-like bundle of multiple axons wrapped in layers of connective tissue and fat
29
How many types of nerves are there and what are they?
3 types, sensory nerves, motor nerves and mixed nerves
30
What do sensory nerves do?
they transmit nerve impulses from sense organs to the CNS
31
What do motor nerves do?
they transmit nerve impulses from the CNS to muscles or glands
32
What do mixed nerves do?
they transmit nerve impulses in both directions
33
What are Schwann cells and what do they do?
they wrap around the PNS neurons to form sheaths made of myelin and they speed up transmission
34
How does a nerve impulse work?
begins at the cell body, travels along the axon, and passes to another neuron or effector at the axon terminal
35
What is an action potential?
an electrochemical event that is created by a sudden change in the concentration of ions on opposite sides of a neurons cell membrane
36
What are the steps of the action potential?
resting potential, depolarization, repolarization, hyperpolarization
37
What is happening to the neuron during resting potential?
the neuron is not firing, action potential is not occurring, a sodium-potassium pump actively pumps 3Na+ ions out of the cell and 2K+ ions in the cell to keep the cell balanced
38
What is the charges on either side of the cell during resting potential?
positively charged outside and negatively charged inside
39
What is the voltage level during resting potential?
-70mV
40
What happens at the threshold?
When a stimulus is triggered, Na+ channels open allowing the ions to rush into the cell, causing a small depolarization
41
What does the voltage rise to during the threshold?
-55mV
42
What happens during depolarization?
Once the -55mV is hit, more Na+ gated channels open allowing more ions to rush into the cell causing an even more depolarization
43
What is the voltage during depolarization?
+35mV
44
What happens during repolarization?
when the voltage hits +35mV, the cell begins to repolarize and Na+ gated channels close and K+ gated channels open and potassium ions rapidly diffuse out of the cell which decreases the voltage
45
What is the voltage during repolarization?
-70mV
46
What happens during hyperpolarization?
The K+ gated channels stay open for slightly longer than needed to bring the membrane back to the resting potential
47
What is the voltage during hyperpolarization?
-75mV
48
What happens after hyperpolarization?
the sodium potassium pumps regulate the voltage back to -70mV and the neuron goes back to being in the resting potential phase
49
What is the refractory period?
the time after an action potential where a neuron cannot fire again
50
What is the absolute refractory period?
a neuron cannot have another action potential due to inactive Na+ channels
51
What is a relative refractory period?
a neuron can have a action potential with larger stimulus due to K+ channels still being open
52
What is the all or none rule?
action potentials occur fully or not at all action potentials don't change sizes
53
What are synaptic bulbs?
knob like tips are the end of axon terminals on the neuron
54
What is the synapse?
the junction between the synaptic bulb of one neuron and another neuron or an effector
55
What is the synaptic cleft?
a tiny gap where a nerve signal is transmitted
56
What are chemical messengers?
neurotransmitters
57
What is the spinal cord?
a cord of nerve tissue that passes down from the brain through a bony column formed by the vertebrae
58
What is the spinal cord composed of?
interneurons and motor neurons
59
What are the 2 functions of the spinal cord?
connect the PNS to the CNS and process some forms of sensory information and sends out responses
60
What are meninges?
3 layers that surround the brain and spinal cord
61
What does meninges do?
cushion, protect and nourish the nerve tissue
62
What are the 3 layers of meninges?
the dura mater, the arachnoid mater and the pia mater
63
What is the dura mater?
the outermost layer, made of tough fibrous connective tissue
64
what is the arachnoid mater?
the middle layer, net-like with vessels that reabsorb cerebrospinal fluid
65
What is the pia mater?
the innermost layer, very thin layer with numerous blood vessels
66
What is the cerebrospinal fluid and where is it found?
a clear watery fluid that is found in the central canal of the spinal cord and within the cavities of the brain
67
Where is the CSF made?
the choroid plexus
68
What is the CSF functions?
cushions and protects the brain and spinal cord from injury, supplies nutrients to nervous system issues and removes waste products from nervous system metabolism
69
What is the outer material of the spinal cord and what is it made of?
the white mater, it is composed of sensory nerves and motor nerves that have myelin sheaths
70
What is the inner material of the spinal cord and what is it composed of?
the grey mater, it is composed of interneurons that have no myelin sheaths
71
Where do nerve roots extend from?
the posterior and anterior horns of the spinal cord
72
Where do dorsal roots come from and what do they contain?
they are posterior, they are closest to the back of the body, they contain sensory neurons whose cell bodies are clumped in bulb-like regions
73
Where do the ventral roots come from and what do they contain?
They are anterior, they are closest to the front of the body, they contain motor neurons whose cell bodies are found in the grey matter if the spinal cord
74
What is the brain?
the processing center of the nervous system
75
What is the brain the site of?
consciousness, sensation, coordination and memory
76
What are the 3 regions of the brain?
the cerebrum, the cerebellum and the brain stem
77
What is the largest part of the brain?
the cerebrum
78
What does the cerebrum control?
complex mental functions like thought, reasoning, memory, and determines a persons intelligence and personality
79
What does the cerebrum contain?
interneurons for interpreting sensory information from sense organs initiating voluntary responses to stimuli through effectors
80
What are the 3 main parts of the cerebrum?
the cerebral cortex, the basal ganglia and the medullary body
81
What is the cerebral cortex?
the outer surface of the cerebrum which contains folds and deep grooves
82
How is the cerebral cortex divided?
Into the left and right hemispheres
83
What is the corpus callosum?
connect the left and right hemispheres with a bridge of nerve fibers
84
What are the 4 lobes of the brain?
the frontal lobe, the parietal lobe, the temporal lobe and the occipital lobe
85
What is the function of the frontal lobe?
deliberate movements, conscious thoughts, emotions
86
What is the function of the parietal lobe?
sensory processing, body orientation, attention
87
What is the function of the temporal lobe?
hearing, speech, visual and auditory memory
88
What is the function of the occipital lobe?
vision and object recognition
89
What are the specialized areas of the cerebrum?
the motor cortex, the somatosensory cortex, brocas area and wrenickes area
90
What is the function of the motor cortex?
controls and execution of voluntary movements
91
What is the function of the somatosensory cortex?
reception and interpretation of sense of touch
92
What is the function of the brocas area?
generating and articulating oral speech and language
93
What is the function of wrenickes area?
understanding written and spoken speech and language
94
What is the cerebellum?
a large mass of grey and white matter located posterior to the brain stem
95
What is the function of the cerebellum?
the coordination center for all body movements
96
What is the brain stem?
the lower section of the brain and connects the cerebrum to the spinal cord
97
What is the function of the brain stem?
the relay center between the CNS and PNS and acts as a control center for many involuntary functions
98
What are the 3 parts of the brain stem?
the midbrain, pons and the medulla oblongata
99
What is the medulla oblongata?
the bottom portion of the brain stem
100
What does the medulla oblongata do?
conducts signals between the spinal cord and cerebrum and controls automatic functions like breathing, heart rate and blood pressure
101
What is the pons?
the middle bulge of the brain stem
102
What is the function of the pons?
conducts signals between the medulla, cerebellum and the cerebrum
103
What is the midbrain?
the top portion of the brain stem
104
What does the midbrain do?
conducts signals between the spinal cord and the cerebrum, controls automatic functions such as vision, hearing, motor control, alertness and temperature
105
What does the endocrine system consist of and what do they do?
glands and cells that secretes hormones into the bloodstream
106
What are endocrine glands?
glands that produce messengers (hormones) that are released into the blood and kept inside the body
107
What are the 2 types of hormones?
Steroid and non-steroid hormones
108
What is the actions of steroid hormones?
Fat soluble, passes easily through the cell membrane, hormones bind to receptors or proteins to form a hormone-receptor complex that can turn a gene off and on
109
What is the actions of the nonsteroid hormones?
Water soluble, binds with receptors on the cell membrane to form an hormone-receptor complex outside of the cell to trigger a second messenger molecule that alters cell metabolism and activity
110
What is the location of the hypothalamus?
below the thalamus, part of the nervous system
111
what is the function of the hypothalamus?
links the nervous system to the endocrine system by the pituitary and produces releasing hormones that stimulate the release of pituitary hormones into the blood
112
What hormones do the hypothalamus produce?
releasing hormones, anti-diuretic hormone and oxytocin
113
What is the effects of the releasing hormone?
increases the release of pituitary hormones
114
what is the effects of the anit-diuretic hormone?
increased blood volume and pressure
115
What is the effects of oxytocin?
increases contractions of the uterus and milk released
116
What is the location of the anterior pituitary?
inside a bony structure at the base of the brain
117
What is the function of the anterior pituitary?
responding to signals from the hypothalamus, releases hormones to signal other glands
118
What are the hormones produced by the anterior pituitary?
growth hormone, melanocyte-stimulating hormone, adrenocorticotrophic hormone, follicle stimulating hormone, luteinizing hormone and prolactin
119
What is the effects of the growth hormone?
increases growth of organs and increase blood glucose
120
What is the effects of the melanocyte-stimulating hormone?
increases synthesis of melanin in the skin
121
What is the effects of the adrenocorticotrophic hormone?
increases hormones by the adrenals
122
What is the effects of the follicle stimulating hormone?
sperm and follicle development and estrogen
123
What is the effects of the luteinizing hormone?
increases testosterone, ovulation and estrogen
124
What is the effects of prolactin?
increases breast development and milk production
125
What is the location of the posterior pituitary?
inside a bony structure at the base of the brain
126
What is the function of the posterior pituitary?
responding to signals from the hypothalamus, releases hormones to signal other glands
127
What hormones are stored in the posterior pituitary?
antidiuretic hormone, oxytocin
128
What is the location of the thyroid?
in the next near the larynx
129
What is the structure of the thyroid?
2 wing like lobes that are connected by a band of tissues with functional units called follicles
130
What are the hormones produced by the thyroid?
thyroxine, triiodothyronine and calcitonin
131
What is the effects of the thyroxine and triiodothyronine?
increasing cellular and body metabolism
132
What is the effects of calcitonin?
decreasing blood calcium and increasing bone calcium
133
What is the location of the parathyroid?
behind the thyroid
134
What is the structure of the parathyroid?
4 tiny lumps of gland tissue, each the size of a pea
135
What is the function of the parathyroid?
Does numerous antagonistic things compared to the thyroid?
136
What is the hormone produced by the parathyroid?
the parathyroid hormone
137
What is the effects of the parathyroid hormone?
increased blood calcium and increased calcium release from the bones
138
What is the location of the pancreas?
in a fold beneath the stomach
139
What is the functions of the pancreas?
produces enzymes for digestion and endocrine hormones
140
What are the hormones produced by the pancreas?
insulin and glucagon
141
What is the effects of insulin?
decreasing blood glucose levels and increasing glucose absorption by cells
142
What is the effects of glucagon?
increasing blood glucose levels and increasing formation of glucose
143
What is the location of the adrenals?
one on top of each kidney
144
What is the structure of the adrenals?
inner tissue called the medulla, outer tissue called the cortex
145
What is the functions of the adrenals?
the medulla secretes amine hormones and the cortex secretes steroid hormones
146
What are the hormones produced by the adrenals?
epinephrine, aldosterone, cortisol and androgens
147
What is the effects of the epinephrine?
the fight or flight mechanism
148
What is the effects of aldosterone?
regulates blood electrolytes
149
What is the effects of cortisol?
increasing blood glucose levels and has anti-inflammatory effects
150
What is the effects of the androgens?
influences sex characteristics
151
What is the location of the ovaries?
held on either side of the uterus
152
What is the structure of the ovaries?
a pair of oval shaped structures
153
What is the function of the ovaries?
responsible for producing egg cells that grow inside of a follicle
154
What hormones are produced by the ovaries?
estrogen and progesterone
155
What is the effects of estrogen?
increasing development and maturation of female sexual characteristics
156
What is the effects of progesterone?
increasing bodily conditions needed for maintained pregnancy
157
What is the location of the testes?
held outside the body in the scrotum
158
What is the structure of the testes?
a pair oval shaped structures
159
What is the function of the testes?
Responsible for producing sperm cells in response to the pituitary, produce male sex hormones
160
What hormone does the testes produce?
testosterone
161
What is the effects of testosterone?
increasing development and maturation of male sexual characteristics
162
What is the location of the thymus?
behind the sternum in the upper thorax
163
What is the structure of the thymus?
2 wing like lobes
164
What is the function of the thymus?
produce and release hormones into the blood, involved in immune responses
165
What hormone does the thymus produce?
thymosins
166
What is the location of the pineal?
found in the midbrain and attached to the thalamus
167
What is the effect of thymosins?
a family of hormones that promotes the development of immune cells called T-lymphocytes
168
What is the structure of the pineal?
a pea sized gland that is pine cone shaped
169
What is the function of the pineal?
produces melatonin from the amino acid tryptophan and influences pituitary hormones
170
What is the hormone produced by the pineal?
melatonin
171
What is the effects of melatonin?
influences the day-night cycle and regulates the activity of other hormones
172
What is the function of the urinary system?
helps maintain homeostasis, regulates the composition and concentration of substances in body fluids
173
What are the 4 major functions of the urinary system?
filtration, excretion, hormones and homeostasis
174
What is filtration?
separates waste products from blood to form a filtrate
175
What is excretion?
stores and removes urine from the body
176
What is hormones in the urinary system?
the production of 2 essential hormones
177
What is homeostasis in the urinary system?
control of fluid levels, blood pH and pressure
178
What is included in the excretory system?
the lungs and skin
179
What are the kidneys and where are they found?
2 bean shaped organs roughly the size of a fist and found under the ribcage on either side of the spinal cord
180
What are the 2 regions of the kidney?
the outer cortex and the inner medulla
181
What is the medulla divided into?
triangular sections called renal pyramids
182
What are the renal pyramids separated by?
inward extensions of the cortex called renal columns
183
What is found in the cortex?
Nephrons
184
What is nephron and where is it located?
the basic functional filtration unit of the kidney and is located where blood is filtered and urine is produced
185
What are the main jobs of the nephron?
filter the blood, removes wastes, removes excess substances, returns useful substances and eliminates wastes in the urine
186
Where does the renal pyramid drain into?
The mink calyx (where urine is first collected)
187
Where do several minor calyxes drain into?
major calyx
188
Where does the major calyces drain into?
the renal pelvis
189
Where does unfiltered blood enter the kidney?
the renal artery
190
Where does the blood flow around in the renal pyramids?
interlobular arteries and arcuate arteries
191
What do the interlobular and arcuate arteries subdivide into?
smaller afferent aterioles
192
Where do the afferent arterioles enter the nephrons?
the glomerular capillaries
193
What are the 4 steps for the formation of urine?
filtration, reabsorption, secretion and excretion
194
What is reabsorption?
the process of the blood reclaiming useful substances from the filtrate
195
What is secretion?
the process of substances actively pushed out of the blood and into the filtrate?
196
Where does urine go when it leaves the kidneys?
it enters a pair of slender tubes called ureters that connects to the bladder
197
What is the bladder and what does it do?
an elastic, muscular sac that sits on the pelvic floor and stores urine
198
What do the kidneys nephrons produce?
urine
199
What is urine?
a sterile, liquid byproduct of metabolism in humans
200
How much urine is produced per day?
1.5 liters
201
What is urine made of?
95% water and 5% solids like urea, ions and salts
202
What is urinalysis?
the study of the composition of urine
203
What are urine tests used for?
to check overall health, diagnose new conditions and monitor existing ones
204
What do the kidneys help maintain and how?
the body's blood pressure and blood volume by changing the volume and concentration of urine that they produce
205
What happens when blood pressure and volume is too high?
kidneys produce larger volumes or urine to cause it to decrease
206
What happens when the blood volume and pressure is too low?
kidneys produce smaller volumes of urine to cause it to increase
207
What are the 3 main mechanisms that help regulate urine production?
Renal autoregulation, antidiuretic hormone and renin-angiotensin-aldosterone
208
How do the kidneys respond to changes in blood pressure?
by dilating or constricting the afferent and efferent arterioles at the glomerulus, ensuring that the rate of flow does not change
209
What is the ability for the kidneys to respond to changes in blood pressure?
renal autoregulation
210
What does renal autoregulation operate at?
the normal blood pressure range of 80-180 mmHg
211
What is the regulation of blood osmolarity?
the concentration of solutes dissolved in the bloodstream
212
What happens when blood osmolarity is high?
blood volume tends to be low
213
What happens when blood osmolarity is low?
blood volume tends to be high
214
Where is blood osmolarity monitored?
the hypothalamus
215
What happens when osmolarity is high?
the hypothalamus stimulates the release of ADH by an endocrine gland called the pituitary, ADH travels through the blood and reaches the kidney and acts on both the distal convoluted tubule and collecting duct
216
What does ADH cause in the distal convoluted tubule and collecting duct?
to be more permeable to water
217
How does ADH cause in the distal convoluted tubule and collecting duct?
stimulates the addition of extra protein channels in their membraned called aquaporins which causes more water to be reabsorbed into the blood
218
What does greater water reabsorption mean?
higher blood volume and lower blood osmolarity
219
What specialized cells monitor blood pressure by the afferent and efferent arterioles?
juxtaglomerular complex
220
What does JGC cells do when blood pressure is detected?
they release the enzyme renin into the blood
221
What does renin do?
travels to the liver where it catalyzes the production of a hormone called angiotensin 1
222
Where is angiotensin 1 converted into angiotensin 2?
the lungs
223
What does angiotensin 2 do?
it travels to the adrenals glands which triggers the release of aldosterone
224
What does aldosterone stimulate and then cause?
the reabsorption of Na+ ions in the distal convoluted tubule which causes water to reenter the bloodstream by osmosis
225
What is the result of water reentering the bloodstream?
blood volume and blood pressure increases
