Homeostasis Flashcards
(106 cards)
1
Q
What is homeostasis?
A
our bodies tendency to maintain a certain range of internal conditions or environments.
2
Q
What are internal variables?
A
body temperature
internal pH
internal concentrations of various ions
hydration
blood pressure
glucose levels in the blood.
3
Q
what are Negative feedback loops?
A
work to counteract changes to normal system/body conditions
4
Q
what are Positive feedback loops?
A
amplify the initiating stimuli and they move the system away from its normal starting state (these are not as common)
5
Q
what makes up the nervous system?
A
brain
spinal chord
Nerves
6
Q
what are the two nervous systems?
A
central nervous system
peripheral nervous system
7
Q
what makes up the central nervous system?
A
brain
spinal chord
8
Q
what makes up the peripheral nervous system?
A
network of nerves
9
Q
what is the peripheral nervous system divided into?
A
somatic and autonomic systems
10
Q
what makes up feedback loops?
A
a sensor (receptor)
a control centre
an effector
11
Q
what is a sensor?
A
a structure that detects changes and sends signals to the control centre using sensory neurons
12
Q
what is a control centre?
A
the part of the central nervous system that determines the actions necessary in order to maintain a range of values.
13
Q
what is the effector?
A
receives signals from the control centre via motor neurons. Effectors (ex. muscles, glands) bring about change in response to signals from the control centre
14
Q
what are the parts of a neuron?
A
Dendrite
Axon
cell body
nucleus
node of ranvier
axon terminal
myelin sheath(schwan cell)
15
Q
what generate action potential?
A
culmination of depolarizations received by the dendrites.
16
Q
what makes up a nerve?
A
A nerve is made up of many axons bundled together.
17
Q
what is resting potential?
A
no action potential
18
Q
is the outside or inside of the axon more negative?
A
inside
because there are more positive ions(K+ and Na+) outside
19
Q
-70 is…..?
A
resting potential
20
Q
-55 is…..?
A
depolarization
21
Q
-90 is…..?
A
hyperpolarization
22
Q
refractory period is….?
A
-70
23
Q
what occurs during resting potential?(1)
A
resting potential is the electric potential across the membrane when the neuron is not stimulates
24
Q
(2) action potential
A
takes place when threshold potential is reached (-55)
25
(3) depolarization
sodium channel proteins open allowing sodium ions to move into the axon
26
(4) refractory period
sodium channels close once electric potential flips to +30. Chanel will not open for a brief period
27
(5) repolarization
potassium channels now open and potassium ions move along their electrochemical gradient
28
(6) hyperpolerization and repolarization
potassium channels close (-90) and Na/K pumps work to restore resting potential
29
what do schwan cells do?
wrap around the axon
30
what makes up myelin sheath
schwan cells
31
what would happen in a myelinated axon?
A myelinated axon would have the action potential “skip” along the axon, where the exposed portions of the axon (Nodes of Ranvier) undergo depolarization/repolarization.
32
what are the spaces between schwan cells called?
Nodes of ranvier
33
what do the nodes of ranvier do?
block off channels and only allow Na and K to move through nodes of ranvier. Mylenation causes ions to move out of the cell faster.
34
do all synaptic terminals have the same neurotransmitters
Different synaptic terminals will have different neurotransmitters. Different postsynaptic dendrites will house different types of receptors.
35
what do excitatory neurotransmitters do?
Excitatory neurotransmitters causes the opening of Na+ channels and moves the membrane potential closer towards threshold (-55mV).
36
what are the types of excititory neurotransmitters?
ADRENALINE / NOREPINEPHRINE
GLUTAMATE
DOPAMINE
37
what does ADRENALINE / NOREPINEPHRINE do?
controls alertness and arousal
38
what does GLUTAMATE do?
involved with learning and memory
39
what does DOPAMINE do?
associated with learning, attention, reward and pleasure
40
what do Inhibitory neurotransmitters do?
causes the opening of K+ channels and moves the membrane potential further away from threshold (-55mV).
41
what are the inhibitory neurotransmitters?
SEROTONIN
GABA
DOPAMINE
42
what does serotonin do ?
associated with mood (wellbeing and happiness), hunger, arousal. Serotonin also helps with sleeping.
43
what does GABA do?
a major inhibitory neurotransmitter that reduces neuron excitability by inhibiting nerve transmission.
44
what does DOPAMINE do?
associated with learning, attention, reward and pleasure
45
can some neurotransmitters be excitatory and inhibitory?
yes
46
how do neurons transfer neurotransmitters from presynaptic neuron to postsynaptic neuron?
exocytosis
47
what causes a release of neurotransmitters from the presynaptic membrane?
calcium(Ca+)
48
what drives the movement of neurotransmitters across synaptic self?
diffusion
49
what happens if neurotransmitters bind to receptors that open sodium channels?
it will have an excitatory effect on the post-synaptic membrane
50
what happens if neurotransmitters bind to receptors that open potassium channels?
it will have an inhibitory effect on the post-synaptic membrane
51
what type of neurons are used in the peripheral nervous system?
Sensory and motor
52
what is the role of the cerebrum?
Responsible for learning, memory, consciousness as well as interpretation of sensory information and control of response to that information
53
what is the outer layer of the cerebrum called?
the cerebral cortex
54
how is the cerebrum divided?
left and right halves(hemispheres)
55
what is the role of the cerebellum?
unconscious coordination of posture, movements and reflexes
coordinates voluntary movements & fine movements (ex. Riding a bike)
56
what does the corpus collosum do?
Connects & provides communication between the 2 halves of the cerebrum
57
what is the purpose of the medulla oblongata?
Coordinates reflexes and functions that help maintain homeostasis (ex. Heart rate, breathing rate, breathing, swallowing…)
58
what does pons do?
A relay centre between right and left cerebral (cerebrum) hemispheres, the cerebellum and the rest of the brain
59
what does the midbrain do?
Helps in the processing of sensory information from eyes, ears, and nose
Helps in controlling eye movement and control of skeletal muscles
60
what does the thalamus do?
Connects areas of the cerebral cortex (cerebrum) that are involved in sensory perception and movement with other parts of the brain and spinal cord that also have a role in sensation and movement
61
what does the hypothalamus do?
Regulates body’s internal environment (ex. Blood pressure, heart rate, body temperature, thirst & hunger) as well as emotion.
A major link between the nervous system and the endocrine system (hormones)
62
where is the corpus callosum located?
snake like structure that looks as though it partially surrounds inner part of the brain
63
where is the thalamus?
looks like a misshapen oval and is located just under the corpus callosum
64
where is the hypothalamus?
circular structure located just under the thalamus
65
where is the hippocampus?
short and skinny structure located under neither the hypothalamus
66
where is the pituitary gland?
very small structure which is located under the hippocampus in the cerebrum
67
where is the cerebrum?
known as the little brain and is located near the spinal chord and brain stem
68
what makes up the brainstem?
midbrain
pons
medulla
69
what are the lobes of the cerebral cortex?
frontal
temporal
parietal
occipital
70
what is the role of the frontal lobe?
-Consciousness
-Control of our voluntary movement (walking) & expressive language (speech)
-Judgments we make about what occurs in our daily activities
-Controls our emotional response, self control (Inhibition), reasoning
Intellectual activities & personality
71
what is the role of the occipital lobe?
Responsible for vision
Linked to interpretation of visual information
72
what is the role of the temporal lobe?
Hearing ability
Memory acquisition and recall
Some visual perceptions
Categorization & interpretation of objects
73
what is the role of the parietal lobe?
Location for visual attention
Location for touch perception & temperature awareness
Emotion and interpretation of speech
Integration of different senses that allows for understanding a single concept
74
what type of neurons make up grey matter?
unmylenated neurons
75
what type of neurons make up white matter?
myelinated neurons
76
what is the peripheral nervous system?
the network of nerves that carry information from the sensory organs/tissues (sensors) to the central nervous system (CNS) and sends information from the CNS to muscles & glands (effectors).
77
what are motor neurons?
transmit signals from the spinal cord to skeletal and smooth muscles (such as those in your stomach)
78
what are sensory neurons?
takes signals from sensory organs and transmits them to the central nervous system (brain and spinal cord)
79
what does the somatic nervous system do?
part of the peripheral nervous system that provides voluntary movement of skeletal muscles.
80
what does the autonomic system do?
part of the peripheral nervous system that takes on involuntary functions involving secretions from glands, movement of smooth muscle and cardiac muscle.
81
what is the function of the sympathetic nervous system?
sympathetic nervous system controls the fight or flight response and prepares the body for stress
82
what is the function of the parasympathetic system?
Restores normal balance back to the body
meaning that is brings body back to a calmer state
83
what neurotransmitters are used in the sympathetic system?
acetylcholine and norepinephrine
84
what neurotransmitters are used in the parasympathetic system?
acetylcholine
85
what happens in the sympathetic system?
increases heart rate
increases release of glucose
dilates pupils
releases bladder sphincter
increases blood flow to the skin
causes adrenal gland to release epinephrine & norepinephrine
86
what happens in the parasympathetic system?
decreases heart rate
decreases release of glucose
constricts pupils
contracts bladder sphincter
decreases blood flow to the skin
has no effect on adrenal gland
87
what glands involve the stress response?
adrenal glands
88
what are the two parts that the adrenal glands are divided into
adrenal cortex (the outer layer of the adrenal gland) and the adrenal medulla (the inner layer).
each layer releases hormones that support the body during times of stress
89
short term stress response in the adrenal glands
hormones (epinephrine and norepinephrine) released from the adrenal medulla.
90
what is the chronic stress response?
this results in more changes to body processes such as increased blood pressure, increased levels of glucose in the blood, etc. These are coordinated by the release of ACTH (adrenocorticotropic hormone), glucocorticoids and mineralocorticoids from the adrenal cortex.
91
what does epinephrin do?
when released it causes an increase in heart rate, opening of airways, increase in blood pressure, and sugar metabolism.
92
what does norepinephrine do?
similar to epinephrine (adrenaline) is also released as part of the fight or flight response. It also impacts circulation, sugar metabolism and increased blood pressure.
93
what hormones are used to regulate acute stress?
epinephrine and norepinephrine
94
what hormones are used to regulate chronic stress?
Glucocorticoid
Cortisol
Mineralocorticoid
95
what do Glucocorticoid hormones do?
these are steroid hormones released by the adrenal cortex that help reduce inflammation
96
what does cortisol do?
a steroid hormone that suppresses the immune system, and helps breakdown fat, protein, and carbohydrates in order to generate more glucose.
97
what does Mineralocorticoid do?
a steroid hormone released by the adrenal cortex that influence salt and water balances
98
what is the endocrine system?
The endocrine system is a system of glandular tissues that produce and secrete special messenger molecules called hormones, into the blood.
99
what are non-target hormones?
act upon Many different cells in the body
100
what are target hormones?
act upon a specific tissue
101
what is the role of steroid hormones?
lipid-based and can easily move through cell membranes and into the cell where they bind with specific receptor proteins and promote changes in the cell
102
what is the role of protein based hormones?
must bind to receptor proteins on the cell membrane which goes on to start a number of reactions inside the cell.
103
where in the brain do hormones come from?
hypothalamus,
pituitary
and pineal gland
104
where are hormones released?
brain -
thyroid and parathyroid glands (located near the voice box)
adrenal glands (located on the kidneys)
pancreas (located near the liver)
ovaries and testes
thymus gland
105
how are hormones regulated?
through positive and negative feedback loops
106
what is the role of tropic hormones?
to target endocrine glands to release other hormones
