a&p fall final Flashcards
1
Q
what are common characteristics of connective tissue?
A
all arise from embryotic tissue (mesenchyme)
highly vascularized
composed mainly of extracellular matrix that allows it to bear weight and withstand tension
2
Q
list the structural elements of CT
A
ground substance, cells, and fibres
3
Q
what are the CT found in the body?
A
areolar, adipose, reticular, dense reg, dense irreg, and elastic
also cartillage, bone, and blood
4
Q
what is ground substance?
A
ground substance- gel like material that fills the space between cells. consists of interstitual fluid, adhesion pros, proteoglycans, and protein fibres.
5
Q
what are the cells in CT? what do they do?
A
cells- “blasts” are immature cells that actively work. “cytes” are mature cells arent active and maintain health of matrix. fibroblasts in CT proper, chondroblasts in cartiallge, and osteoblasts in bone.
6
Q
what are the fibres in CT?
A
fibres- fibre and ground sub make up extracellular matrix, collagen fibres provide strength, elastic fibres provide stretch, and reticular fibres provide branches between CT and other tissue and found where filtration occurs
7
Q
what is a cutaneous mem?
A
a dry mem known as skin. consists of keratinized
stratified squamous
epithelium over areolar connective tissue and dense irregular connective tissue.
help protect the rest of the body’s tissues and organs from physical damage.
8
Q
what is a mucous mem?
A
wet membranes that line body cavities that open to the
outside of the body.
made of stratified squamous
or simple columnar epithelia over a layer of areolar connective tissue called lamina propria
9
Q
what is a serous mem?
A
lines the walls of cavities and organs within closed ventral body cav.
made of simple squamous epithelium on top of a layer of areolar CT
The cavity between layers is filled with serous fluid to reduce friction
10
Q
what is a Synovial membrane?
A
line joint cavities and secrete synovial fluid to lubricate and support bones that move. They lack epithelium and are considered a specialized connective tissue
11
Q
what is muscle tissue? what are the 3 types?
A
Muscle tissues are highly cellular, well-vascularized tissues responsible for movement. contains myofilaments made of actin and myosin responsible for contraction.
skeletal, smooth, and cardiac
12
Q
what is skeletal muscle tissue?
A
voluntary muscle that attaches to the skeleton and when they contract cause movement of the skeleton. aka musc fibres
composed of long cylinder cells that have multiple nuclei around the edges. has visible striations.
13
Q
what is smooth muscle tissue?
A
non voluntary, unstriated,
uninucleate and spindle-shaped cells. They are found in
the walls of the hollow organs, in dig tract, pushes food thru tract by contracting and relaxing (peristalsis)
14
Q
what is cardiac muscle tissue?
A
striated, single nucleus, and branched.
located linging walls of the heart, has intercalated discs where the cardiac cells join at gap junctions and desmosomes. the contractions of the musc pump blood thru the body, involuntary
15
Q
what is nervous tissue?
A
main component of nerv sys, has CNS and PNS, regulates and controls body functions. contains neurons and neuroglial cells.
found in the brain, spinal chord, and nerves
16
Q
what 2 ways does tissue repair occur?
A
regeneration, in which damaged cells are replaced with the same type of cell.
fibrosis, which replaces damaged cells with fibrous connective tissue. happens in tissues that do not regenerate
17
Q
what is the first step of tissue repair?
A
Inflammation
prepares the area for repair by
dilating blood vessels and increasing in blood vessel permeability. Inflammatory chemicals are released by damaged tissues.
Scabbing and clotting occurs.
18
Q
what is the second step in tissue repair?
A
Organization
process that replaces the blood
clot with granulation tissue (new capillary-rich tissue), restoring blood supply. Macrophages phagocytize dead and dying cells and, Fibroblasts produce collagen fibres to in a process called fibrosis, and surface epithelial cells multiply and migrate over
the granulation tissue.
19
Q
what is the final step in tissue repair?
A
Regeneration and/or fibrosis
restores tissue the scab detaches as fibrous tissue matures.
Epithelium thickens and begins to resemble adjacent tissue
20
Q
what tissues regen well?
A
epithelial tissues, bone, areolar connective tissue,
dense irregular connective tissue, blood-forming
tissue
21
Q
what tissues do not regen?
A
cardiac muscle and nervous tissue of brain and spinal cord
22
Q
what are the two layers of skin?
A
super- epidermis
deep- dermis
23
Q
what is the subcutaneous tissue?
A
aka hypodermis, consisting mostly of adipose tissue that anchors the skin to underlying muscle, allows skin to slide over muscle, and acts
as a shock absorber and insulator
24
Q
what are the cells in epidermis?
A
keratinocytes- keratinized strar sqaumous
melanocytes- synth pigment and prtect against UV
longerhorns- WBC
tacktile- sensory
25
what are the layers of epidermis starting with the deepest?
stratum basale
stratum spinosum
stratrum granulosum
stratum lucidum
stratum corneum
26
what is the stratum basale layer?
attached to dermis
always actively dividing(mitotic)
has melanocytes
27
what is the stratum spinosum layer?
3-5 cells thick
has keratinocytes and melanocytes
web-like system of intermediate
pre-keratin filaments attached to desmosomes. This allows them to resist tension and pulling.
28
what is the Stratum granulosum layer?
4-5 cells thick
Cells flatten, nuclei and
organelles disintegrate and keratinization begins
Cells above this layer die because they are too far from dermal capillaries to survive
29
what is the Stratum lucidum layer?
only found in skin that covers the palms , soles of the feet and
the surfaces of fingers and toes
It consists of thin, translucent band of two to three rows of clear, flat, dead keratinocytes
30
what is the Stratum corneum layer?
the outermost layer of the epidermis,constantly being replaced by cells beneath
31
what is ther dermis?
composed of strong, flexible
connective tissue and is
supplied with blood vessels,
nerves and lymphatic
vessels
it has two layers, papillary layer and reticular layer
32
what is the papillary layer?
superficial layer
composed of areolar connective tissue that forms dermal papillae that result in fingerprints.
33
what is the reticular layer?
80% of the thickness of the dermis
It consists of dense fibrous connective tissue with stretchy elastic fibers and durable collagen fibers
has felxure lines which are found at folds of joints on your hand
has tention lines caused by collagen fibres running parrallel to skin surface. easily allows for cuts to be made without scaring, and dermal tears are called striae aka stretch marks
34
what is melanin?
a group of skin and hair pigments that are brown or black (eumelanin) or pinkish red
(pheomelanin)
35
how does melanin protect against UV?
physical barrier that scatters UV and reduces UV penetration thru epidermis
36
why are there different skin colours?
skin colour differences are due
to the amount and type of melanin
37
what is carotene?
a yellow-orange pigment found in
certain foods
38
why is there a pinkish hue seen in fair skin?
due to hemoglobin in blood seen thru transparency of skin
39
what gives skin its colour?
melanin and hemoglobin
40
what is Cyanosis? Jaundice? Erythema?
-blue skin due to low O
-yellow skin due to liver disorder
-red skin due to anger or fever
41
what is Pallor? bronzing? bruising?
-pale skin
-steroid hormones causes over-
expression of melanin
-Bleeding or coagulated blood under the skin
outside of the blood vessels (hematoma)
42
what are the parts of a hair follicle?
peripheral connective tissue sheath- a thickened
basement membrane from the dermis
inner epithelial root sheath- derived from the epidermis
43
what is hair? what is its function?
flexible strands of dead keratinized cells produced by hair folicules made of hard keratin
-insulating against heat loss
-protecting head against physical trauma
-shielding skin from sunlight
44
what are the 2 main regions of hair?
hair shaft- projecting from skin
hair root- embedded in skin
45
what are the 3 layers of hair starting deepest?
medulla (in thick hair)
cortex
cuticle
46
how does hair get its colour?
melanocytes at the base of the hair follicle, combos of diff melanocytes create diff hair colours
47
what is a hair follicule?
folds down from the epidermis into the dermis and occasionally into the hypodermis
48
hair bulb
contains the dermal papilla and hair matrix,regulates hair growth
49
hair matrix
mitotically active in the hair bulb
50
hair papilla
a knot of capillaries that supplies nutrients to growing hair
51
what is the muscle that allows hair to stand up?
arrector pili muscle
52
what is vellus hair?
pale, fin, thin hair
53
what is terminal hair?
long, coarse, thick hair
54
what does hair growth depend on?
age, sex, location, hormones, and nutrition
55
how does hair on your head grow?
in increments;
grow continuously for 2-7 years, then slow down for 2-3 weeks and rest for 2-4 months before growing begins again.
56
why do ppl bald or have thinning hair?
hair has a limited amount of cycles.
bald- genetic,
thinning-hair is not replaced as quickly as it is lost, which leads to hair thinning and some degree of
balding
57
what are Sebaceous glands?
holocrine glands that secrete sebum (oil) into a hair follicle or to a pore on the surface of the skin to softens and lubricates the hair and skin, slows water loss, reduce friction, and is bactericidal
58
what are Eccrine sweat glands?
merocrine glands
ducts are connected to glands to produce sweat
regulated by the
sympathetic nervous system and is used to prevent
the body from overheating
59
what are Apocrine sweat glands?
only in armpit, They produce a fat and protein-rich true sweat causing body odur
starts at puberty
60
what are the two modified sweat glands?
Ceruminous glands- are modified apocrine sweat glands found lining the ear canal that secrete ear wax
Mammary glands- are modified apocrine sweat glands that secrete milk
61
what is a nail?
scale-like modification of the epidermis that forms a protective covering on the dorsal side
of the distal finger or toe
62
do toe or finger nails grow faster?
fingernails
63
what is the structure of nails?
made up of hard keratin and have a free edge, a nail body attached to the skin, and a root
embedded in the skin
64
what is the nail matrix?
proximal part of nail bed, mito active and responsible for gorwth
65
what is the free edge of the nail?
extends past finger or toes
66
what is the nail body?
attached to skin
67
what is Proximal nail fold and lateral nail folds
the skin covers over the edges of the nail, holds in place
68
what is Lunula on the nail?
white half circle on nail bed, thickest
69
what is the eponychium(cuticle)?
the stratum corneum of
the epidermis at the proximal nail fold
70
what is the nail root?
not viable, embedded in skin where the nail grows
71
what is the nail bed?
the skin below the nail body
72
what is the hyponychium?
secures nail to finger
73
what is the distal phalanx?
bone under nail
74
what are the 3 barriers skin provides?
protects from external enviro,
chem- protect from UV by secreting secretions low in pH
physical- hardness of the
keratinized cells
biological- living cells (WBC) that change and adapt that look for things that have gotten thru the physcial barrier
75
what are the 5 functions of skin?
barrier
regulation and sensation
metabolism
body temp regulation
heat exchange
76
how does skin regulate body temp?
by manufacturing sweat to
cool the body and causing constriction of dermal
capillaries to prevent heat loss
77
what provides sensation in skin?
cutaneous
sensory receptors
78
how does skin contribute to metabolism?
makes vit D precurser when exposed to sunlight
can be a blood reserve (can hold 5% of blood) to be used when needed like in exercise
79
what is apart of core body?
skull, abdom and thorasic cavities
37 degrees
vital organs that must be protected
80
what is the shell?
skin, has lowest body temp
81
what are the 4 mechanisms of heat exchange?
radiant- heat exchange from skin to external enviro
conductive- flow of warmth from warmer to cooler objects
convective- movement of warm air away from the body
evaporation- heat loss of fluids from the lungs, oral mucosa, and the skin
82
what is insensible heat loss?
heat loss you dont feel youre losing
ex heat loss when you breathe
83
what is sensible heat loss?
feel yourself cooling down
ex sweating
84
what causes heat cramps
loss of water and salt
85
what are the 3 major types of skin caaner?
Basal cell carcinoma, sqamous cell carcinoma, and melanoma
86
Basal cell carcinoma
least malignant, most common, slow growth, and can be surgically removed
87
Squamous cell carcinoma
can metastasize, derives from keratinocytes in stratum spinosum, seen as scaly red patches, grow rapidly and can be removed or use radiation
88
melanoma
most dangerous, resistant to chemo, cancer of melanocytes, looks like moles or patches
89
what is cancer?
occurs when DNA of a cell is damaged or mutated causing it to grow uncontrolably and dividing rapidly
90
what is a burn?
denatures proteins and cause cell death by heat or electricity or chemical damage
91
what are risks of a burn?
dehydration, fluid loss, and infection
92
what is the rule of nine?
body div into 11 sections that account for 9% of body, except genitals which acc for 1%, used to evaluate burns and estimate
volume of fluid loss
93
what are first and second degree burs?
1- epidermis damage only, red, swells, pain
2- epi and dermis damage, blisters
94
what are partial thickness burns?
burns through epidermis and upper dermis are involved
95
what are third degree burn?
full thickness burns, goes thru epi, dermis, and underlying tissue.
skin turns grey, red, or black and nerve endings are destoryed
96
what are 4-6th degree burns?
all layers of skin, burn the underlying fat, muscle and bone
97
what are the 6 functions of bone?
-support for body and organs
-protection of brain, spine, and organs
-movement for musc action
-mineral and growth storage of calcium and phosphorus
-blood cell formation (hematopoiesis), in red bone marrow
-fat storage in yellow bone marrow, which can be used for energy
98
what is the function of red bone marrow?
produces RBC
99
what is the function of yellow bone marrow?
produces and fat WBC
100
what is compact bone?
outer layer that is smooth and solid
101
what is spongy bone?
inner layer, helps to reduce stress.
consists of pieces of trabeculae instead of osteons
102
what is articular cartilage?
hyaline cartillage, provides support
103
what is periosteum?
covers surface of bone, contains osteogenic cells
hold blood vess and nerves in place thru nutrient foramen openings
contains an outer fibrous layer of
dense irregular connective tissue that secure the membrane to the bone matrix.
anchoring point for tendons and ligaments.
104
what is endosteum?what cells does it contains? what are the functions?
covers internal surface, contains osteogenic cells
covers the trabeculae of spongy
bone. It lines the canals that pass through compact bone
functions in remodelling, repairing and building cells in the membranes
105
what are osteogenic/osteoprogenitor cells?
give rise to all bone cells
can create new cells
mitotically active
found in peri and endo
106
what are osteoblasts?
bone forming cells that secrete un-mineralized bone matrix called osteoid (form matrix)
107
what are osteoclasts?
large ultinuclei cells that produce macrophages to break down bone by releasing dig enzymes and acids
found in resorption bays which is the location that bone is broken away at
when their job is done they die by adoptosis
108
what are osteocytes?
mature bone cells in lacunae that no longer divide.
They maintain bone matrix and
They send information to
osteoblasts and osteoclasts
so bone remodeling can occur.
109
what are periosteal cells?
bone lining cell found on external surface
They are found on bone surfaces in places where there aren’t any osteoblasts or osteoclasts
110
what are endosteal cells?
bone lining cell found on internal surface
They are found on bone surfaces in places where there aren’t any osteoblasts or osteoclasts
111
what is trabeculea?
in spongy bone, gives strength
consists of irregularly arrrenged lamelle and osteocytes connected by cannaliculi
112
what is the diaphysis?
shaft of bone in between the two ends of long bones, hollow.
made of an outer layer of compact bone around a central medullary cavity filled with yellow bone marrow
113
what is the epiphysis?
ends of long bones, has proximal and distal ends.
compact bone around spongy
bone filled with red marrow.
114
what is the medaphysis?
place on the bone where the epiphysis turns to the diaphysis.
includes the epiphyseal line
115
what is the epiphyseal line?
remnant of the childhood epiphyseal plate where bone growth occurs making you taller
after puberty this hardens so you no longer grow.
116
what is the osteoid?
un-mineralized bone matrix made of collagen and calcium that turns bone hard
not mito active
117
what is an osteon?
the structural unit of compact bone that acts as a weight bearing pillar
consists of many rings of bone matrix called lamelle
118
what is lamelle?
rings of bone matrix in an osteon.
contains collagen fibres that run in different directions in adjacent rings, to withstand stress and resist twisting. Bone mineral
salts are found between collagen fibres.
119
what is a central (Haversian) canal?
runs thru centre of osteon
contains blood vessels and nerves
120
what are perforating (Volkmann’s) canals?
lined with endosteum and occur at right angles to the central canal.
transmits blood vessels from the periosteum into the bone and communicates with the Haversian canals
121
what are Lacunae?
small cavities that contain osteocytes
122
what are Canaliculi?
hairlike canals that connect the lacunae to each other and the central canal
123
when do canaliculi form?
when bone matrix hardens and cells are trapped
124
how do bone cels communicate?
maintain contact with each other via cell projections with gap junctions
125
what are the organic components of bone? what do they do?
organic component of bone is the osteoid, which contains ground substance, proteoglycans, glycoproteins and collagen fibers.
allows for flexability and tensile strength
without it, bone would be very brittle and it would break if twisted or stretched.
126
what are the inorganic components of bone? what do they do?
hydroxyapatite, aka mineral salts. consists of tiny calcium phosphate crystals in and around collagen fibres.
responsible for hardness and resistance of compression
127
what is bone remodeling? what cells are involved?
consists of both bone deposit
and bone resorption. It occurs at the surfaces of both the periosteum and the endosteum
osteoblasts and clasts
128
why do hormones regulate bone
remodelling?
Hormonal control of remodelling is mostly used to maintain blood calcium homeostasis and balances activity of parathyroid hormone and calcitonin.
129
what is interstitial lamelle?
lamellae that are not
part of osteon. Some fill gaps between forming
osteons; others are remnants of osteons cut by
bone remodelling
130
what is circumferential lamelle?
layers of lamellae that extend around entire surface of diaphysis that help to resist twisting
131
explain bone depositing
a new matrix is deposited by blasts at the osteoid seam, which is a band of unmineralized bone
matrix that marks areas of new deposition
132
what are Triggers for bone deposit?
mechanical signals, increased
concentrations of calcium and phosphate ions and matrix proteins or enzymes to bind calcium and phosphate ions
133
explain bone remodeling. what cells are involved?
osteoclasts dig grooves as they break down the matrix by secreting dig enzymes and acids
134
what is Wolff’s law?
states that bones grow or remodel in response to demands placed on them (physical stress)
135
what is intramembranous ossification?
is when bone develops from fibrous membrane.
These bones are called membrane bones, forms flat bones like skull and collar bone
136
what is endochondral ossification?
when bone forms by replacing hyaline cart.
bones are called cartilage
(endochondral) bones
forms essentially all bones other than skull and collar bone
137
explain the 4 steps of bone fracture repair
1- hematoma; after the bone
breaks, torn blood vessels
hemorrhage, forming a mass
of blood clotting called hematoma
2-Capillaries grow into the hematoma, fibroblasts secrete collagen fibres to connect broken ends forming Fibrocartilaginous callus tissue
3- fibro callus converts to spongy bone
4- bone remodeling; Excess material is removed and compact bone reconstructs the shaft walls and bone is back to normal
138
what is ossification?
the process of bone tissue formation
formation of bone begins at 2 moths- early adulthood
139
explain the 4 steps of Intramembranous ossification
1- Development of ossification centre: Osteoblasts secrete organic extracellular matrix.
2-Calcification: Calcium and other mineral salts are deposited and extracellular matrix calcifies
(hardens), osteocytes trapped
3- Formation of trabeculae: Extracellular matrix develops into trabeculae that fuse to form
spongy bone
4-Development of the periosteum: Mesenchyme
at the periphery of the bone develops into the periosteum
140
explain the 6 steps in Endochondral ossification
1- development of cart: begins at primary ossification centre in the centre of the shaft. mesenchymal cells develop into chondroblasts
2- Growth occurs by cell
division of chondrocytes.
3-Development of primary
ossification center: In this
region of the diaphysis,
bone tissue replaces
most of the cartilage and calcifies outward from the centre and blood vess run thru
4-formation of medullary (marrow) cavity
5- second oss centre forms in epiphysis
6- forms epiphyseal plate and articular cart that both consist of hyaline cart
141
what is growth hormone?
most important hormone
in stimulating epiphyseal plate activity in infancy and childhood
142
what are the functions of the nervous system?
-controls body functions
-communication sys of the body via electrical and chem signals
-gathers input from sensory receptors
-processes and interprets sensory input to decide appropriate responses
-using motor output to activate effector organs, muscles and glands, to cause a response
143
what are somatic senses?
all over body, pain, temp and touch
144
what are special senses?
eyes or vision, smell, and taste
145
what is the somatic nervous system?
controlable skeletal musc
146
what is the autonomic ner sys?
uncontrolable sys, tells your body to react.
includes Sympathetic, paraympathetic, and Enteric nerv systems
sym (high stress response) and para- (keeps relaxed) control Smooth muscle, cardiac muscle, and glands
ent- controls smooth musc in dig tract
147
what is the CNS?
contains brain and spinal chord control centre that interprets sensory input and dictates motor output.
148
what is the PNS?
contains nerves that extend from brain and spinal cord. Spinal nerves go to and from the
spinal cord and cranial nerves go to and from the
brain
149
what div of the nerv sys carries impulses toward the central nervous system from sensory
receptors located throughout the body?
the sensory (afferent) div
150
what fibres of the nerv sys convey impulses from skin, skeletal muscles and joints to the CNS?
somatic sensory fibres
151
what fibres of the nerv sys carry impulses from organs within the ventral body cavity?
viceral sensory fibres
152
what div of the nerv sys transmits impulses from the CNS to effector organs, such
as muscles and glands?
motor (efferent) div
153
what are the two divs of the motor div of the PNS?
somatic and autonomic
154
what are astrocytes?
regulate the chemical environment around neurons and play a role in exchanges
between neurons and capillaries
155
what are Microglial cells?
monitor health and perform defense functions for neurons, and they migrate toward injured neurons and can transform to
phagocytize (like WBC)
156
what are Oligodendrocytes?
make mylein sheaths in CNS, each can insulate dozens of nearby axons
157
what are Ependymal cells?
line the central cavities of the
brain and spinal cord and help circulate CSF.
can be cilliated and either sqamous of columnar
158
what are Satellite cells?
in PNS, like astrocytes
159
what are Schwann cells (neurolemmocytes)?
make myeline sheaths in PNS also vital to the regeneration
160
what are myelin sheaths?
insulate axons in ner sys.
lipid-rich sheath of plasma membrane that wraps around part of the axon and allows for faster transmission of electrical signals.
Proteins in the myelin help to hold the wrap together.
161
what is a neuron?
specialized cells that conduct messages in the form of electrical impulses throughout the body.
162
what is a dendrite?
receive communication from other cells
convey incoming messages toward cell body as graded potentials
163
what is the function of the neuron cell body?
pools signals and decides which are most important and should move thru to axon
synthesize proteins, membranes and chemicals
164
what are nissl bodies?
like rough ER, found in cytoplasm along w neurofibrils (protein filaments), synthesis of proteins
165
what are Neclei?
clusters of neuron bodies in CNS
166
what are ganglia?
clusters of neuron bodies in PNS
167
what are tracts?
bundles of neuron processes in the CNS, processes are axons or dendrites
168
what are nerves?
bundles of neuron processes in PNS
arry electrical impulses
169
what is the axon?
starts at axon hillock, conducts info to other cells
The ends are called
axon terminals or terminal boutons
170
what is anterograde movement?
away from cell body towards axon
171
what is retrograde movement?
towards cell body from axon
bacteria can use this to get thru brain blood barrier and cause harm
172
what are multipolar neurons?
most common
in CNS
has an axon and 2 or more dendrites
173
what are bipolar neurons?
single axon and dendrite.
in special senses like retina of eye and olfactory mucosa (vision and smell)
174
what are unipolar neurons?
axon and dendrite share same pathway
gets sig quickly
175
what are sensory neurons?
afferent, neurons conduct impulses toward the CNS from receptors
mostly unipolar and cell body in PNS
176
what are motor neurons?
efferent, neurons conduct impulses from the CNS to effectors
multipolar
cell bodies are located in the CNS
177
what are interneurons? aka association neurons
conduct impulses between sensory and motor neurons, or in CNS integration pathways.
mostly in CNS
178
what is a current?
The flow of electrical charge from point to point is called
depends on voltage and resistance
179
what is voltage?
a measure of the amount of difference in electrical charge between two points, called the potential difference
180
what is resistance?
hindrance to current flow
181
what is resting membrane potential?
The difference in electrical charge across the cell membrane, resting membrane potential depends on differences in ion concentration and permeability.
182
how does depolarization affect mem potential?
increases the probability of producing nerve impulses
183
how does polarization affect mem potential?
decreases the probability of producing nerve impulses.
184
what are graded potentials?
short lived changes in membrane potentials that can be depolarizations or hyperpolarizations.
Graded potentials are “graded” based on magnitude of the stimulus corresponds to the magnitude of the response
185
what is action potential? how are they generated?
Higher-stimulus intensity, occurs when it is able to reach depolarization
186
what are ion channels?
allow ions to pass thru mem, selective for a certain type of ion
187
Leakage (non-gated) channels are...
always open
188
what is a Chemically-gated (ligand) ion channel?
open when the correct chemical or ligand binds to the channel
189
Mechanically-gated channels
open when the channel is physically bent or stretched, based on mech stimuli
how we build something that senses touch
190
Voltage-gated channels
open in response to a change in membrane potential
triggered by depolarization
doesnt initiate flow of ions, but if another type of channels does, then voltage gate will get
involved and participate in movement of ions
191
what are receptor potentials?
Graded potentials occurring on receptors of sensory
neurons are called receptor potentials, or
generator potentials.
192
what are postsynaptic potentials.
Graded potentials occurring
in response to a neurotransmitter released from
another neuron are called postsynaptic potentials.
193
Explain how action potentials propagate along neurons
by the movement of the ions through voltage-gated ionic channels embedded in the plasma membrane of the neurons
194
Define absolute and relative refractory periods
ab- while the Na+ channels are open, the cell cannot respond to another stimulus, regardless of how strong.
rel-the Na+ channels are mostly reset, the cell is repolarizing, and a very strong stimulus may reopen Na+ channels and generate another action potential
195
what is saltatory conduction
the way an electrical impulse skips from node to node down the full length of a myleinated axon
196
what is continuous conduction
the way an electrical impulse skips from node to node down the full length of an unmyielenated axon
197
what is synapse?
points of contact between neurons where information is passed from one neuron to the next
198
what are electrical and
chemical synapses?
chem-nformation is transferred via the release of a neurotransmitter from one cell
elec- the cytoplasm of adjacent cells are directly connected by clusters of intercellular channels called gap junctions to give eahco ther info
199
what are excitatory and inhibitory postsynaptic
potentials
ex-Bind to chemically gated ion channels, cause depolarization
in-Hyperpolarize the membrane by making it more
permeable to K+ or Cl−, Moving membrane potential away from threshold
200
Define neurotransmitter
the chems used to send signals in nerves
201
what are the 4 steps to aaction pots?
1- At rest, all gated Na+ and K+ channels are closed
2-Local currents depolarize the axon, and voltage- gated Na+ channels open, allowing Na+ ions to enter the cell.
3-Repolarization restores resting membrane potential as Na+ channels close and K+ channels open.
4-Hyperpolarization occurs when some K+ channels remain open, allowing excessive efflux of K+ to produce a slight dip following the spike.
202
what is a refractory period?
the period of time required before a neuron can generate another action potential.
203
Describe three ways in which ATP is regenerated during
skeletal muscle contraction
creatine phosphate- turn ATP to creatine phos for temp storage, creatine transfer ADP to ATP
anaerobic glycolysis-1 glucose produces 2 ATP and 2 lactic acid, ATP from glycolysis
aerobic respiration- 1 glucose produces 30-32 ATP, 6 CO2 and 6 H2O, good for long term
204
what are functions of muscles?
-produce movement by acting on bones of the skeleton, pumping blood, forming valves or propelling substances through hollow organs.
-maintaining posture
-stabilize joint
-generate heat as a function of their metabolic processes.
-enclose and protect internal organs
205
what are four important
characteristics of muscle tissue?
-responsivness to receive and respond to a stimulus.
-Contractility is the ability to contract forcibly when stimulated.
-Extensibility is the ability to be stretched
-Elasticity is the ability to resume the cells’ original length once stretched.
206
what are fascia?
CT that support muscle tissue
207
what are tendons
attach musc- bone
208
what are ligaments
attach bone to bone
209
what is Endomysium, Perimysium and Epimysium in muscle?
Endomysium- surrounds individual muscle cells
Perimysium- surrounds a bundle of muscle fibres.
Epimysium- encircles entire muscle
210
what are oxidative and glycolytic muscles?
ox-has abundant blood vessels and mitochondria for prolonged use, high endurence
gly- relatively few blood vessels and is good for short bursts of intense activity, short and high intensity
211
what are myofibrils?
contain the contractile elements of the musc cell
212
what are sarcoplasmic reticulum?
regulates the availability of calcium ions(stores ions), surrounds each myofibril
213
what are T tubules of
skeletal muscle fibres?
T tubules is the cell mem that runs into the cell for cell communication to make them contract
214
what causes skeletal musc to have a striated appearance?
myofibrils, alternating dark A bands of myosin and light I bands of actin
215
what is tropomyosin?
wraps around actin filaments, stabilizing them and blocking the myosin binding sites.
216
what is troponin?
chases calcium pulling tropomyosin out of the way to allow myosin to bind to actin to start contraction
217
how do musc fibres contract?
1- The fibre is activated (stimulated) by a nerve ending so that there is a change in membrane pot
2-musc fibre generates action pot in sarcolemma
3-calcium levels rise causing troponin to chase them allowing for contractions
218
what events occur at the neuromuscular junction
1-Action potential arrives at axon terminal at the neuromuscular junction
2-Acetylcholine is released and binds to chemically-gated channels on the sarcolemma, producing a graded response.
3-opens membrane voltage gated channels
4-Acetylcholinesterase breaks down acetylcholine allowing for relaxation
219
Describe how an action potential is generated in a muscle
cell
occurs when ACh binds to ACh receptors at the neuromuscular junction, causing chemically gated ion channels to open. causes depolarization that triggers an action potential, which propagates along the sarcolemma by opening voltage-gated Na+ channels.
220
what is the sarcolemma?
cell mem of skeletal musc cell that froms T tublues
221
what are the A bands? what are the I bands?
dark bands of myosin, light bands of actin
222
what is a sarcomere?
consists of dark (A) and light (I), dark in the mid and light at the ends.
223
what is the H zone?
a slightly lighter region in the centre of the A band, has only thick (myosin) myofilaments
224
what is the M line?
in the middle of the H zone, is where fine protein strands hold adjacent thick (myosin) myofilaments together.
225
what are Z discs?
inside each I band separate sarcomeres.
226
what is the purpose of a titan filament?
to prevent over stretching and anchor myosin
227
what is cross bridging?
myosin feet grab onto actin pros and pulls to contract, called cross bridging
228
what is Excitation-contraction coupling?
is the sequence of events by which an action pot on the sarcolemma results in the sliding of the myofilaments
229
what are the steps in Excitation-contraction coupling?
1-A nerve impulse reaches the axon terminal, The action pot travels across the entire sarcolemma.
2-The action potential travels along T tubules
3-Sarcoplasmic reticulum releases Ca2+, which binds to troponin. Myosin-binding sites on actin filaments are exposed.
4-myosin heads bind to actin filaments. Muscle contraction begins.
230
what is the synaptic cleft?
where the axon terminal and muscle fibre are separated by a narrow gap
231
Describe the sliding filament model of muscle contraction
the thin filaments slide past the thick filaments. Overlap between the myofilaments increases and the sarcomere shortens causing whole musc cell to get shorter
232
describe the steps of cross bridgin
1-Calcium ions bind to troponin and expose the active site on actin filaments, myosin heads attach to actin binding sites, forming the cross bridge
2- head pivots, pulling the thin filament past the thick filament
3- new ATP attaches causing head and actin to detatch
4- ATP primes the myosin head so that it is ready to bind to a new actin binding site next time
233
what is a motor unit?
consists of a motor neuron and all the muscle fibres it innervates, fine control
234
what is a muscle twitch?
the response of a muscle to a single action potential on its motor neuron
235
what are the 3 phases of a musc twitch?
letent period-lag between stimulation and excitation-contraction.
contraction
relaxtion
236
how are graded contractions of a skeletal muscle produced?
a wave summation occurs when impulses reach the muscle in rapid succession, preventing the
cell from relaxing between stimulation events
causes tetanus
237
what are the four major regions of the brain?
cerebral hemispheres
diencephalon
brain stem
cerebellum
238
what are gyri?
raised region in the brain folds
239
what are sulci?
the inward wrinkles in brain
240
what is a fissure?
deep wrinkle that seperates lobes
241
what is the job of Cerebral white matter?
responsible for communication between cerebral areas and the cerebral cortex and lower CNS centres.
242
what are the 3 fibres in cerebral white matter?
association- connect diff parts of same hemisphere
commissural- connect corresponding areas of grey matter in the two hemispheres, allow to func as a whole
projection-connect the cerebral cortex to the lower brain or cord centres
243
what is the largest region of brain?
cerebrum
244
what is the cerebrum?
seperated into left and right halves
has 3 regions; superficial cortex of grey matter, internal white matter, and the basal nuclei
and has 4 lobes; frontal, parietal, temporal, and occipital
245
what is the cerebral cortex?
conscious mind, allowing us to communicate, remember, and understand
246
what is func of basal nuceli?
regulate cognition and emotion, and decide which action you should take
247
lateralization of cortical functioning
each cerebral hemisphere has unique control over abilities not shared by the other half.
248
what does premotor cortex control
musc memory and language
249
association cortex
understanding of the stimulus being felt.
250
vestibular cortex
awareness of balance
251
gustatory cortex
taste
252
what is the diencephalon?
includes the thalamus and hypothalamus
253
what is the thalamus?
sensation, motor activies, learning, decides what to pay attention to, and memory. conduct sensory impulses to the primary sensory areas of the cerebral cortex and transmits motor information from the cerebellum and basal nuclei to the primary motor area of the cerebral cortex.
254
what is the hypothalamus?
integration centre of the autonomic nervous system. It initiates physical responses to emotions, and regulates body temperature.
maintains balance in body sys
regulates pituitary gland
255
what are the 3 regions of the brain stem?
midbrain, pons, and medulla
256
what is corpora quadrigemina?
startle reflex
257
what is the pons?
has pathways between the brain and spinal cord,
gives rise to some cranial nerves, helps w breathing
258
what is the medulla oblinglata?
location of the medullary pyramids, which act as crossover points for corticospinal motor tracts, results in the contralateral control of voluntary movements.
controlls cardiac and respiratory rate
259
what is the cerebellum?
controls motor output, ensuring coordination and balance.
coordinates musc movement
thinking, language, and emotion.
260
what are the 3 lobes within the cerebellum?
posterior and anterior lobes; coordinate body movements
flocculonodular lobes; posture to maintain balance
261
what is the grey matter and white matter locations called in the cerebellum?
grey- outer cortex (called folia) and deeper nuclei
white- arbor vitae
262
what is the limbic system?
involved w emotions, links info together
263
what is the reticular activating
system?
responsible for deciding what youre noticing and what youre ignoring
264
what part of the brain is responsible for language?
Broca’s area and Wernicke’s area
265
what part of the brain is responsible for memory?
hypocampus
266
what are the two types of memory?
declarative-fact based, short term memory and long term memory
Procedural- motor skills
267
what factors affect long term memory?
affected by emotional state while intaking info, best if alert, motivated, excited or surprised, rehearsal, association, or the automatic formation of memory while concentrating on something else
268
what is consciousness? what are the 4 stages?
how awake you are, clinically defined on a continuum that measures behaviour in response to stimuli and ranges through several stages: alertness, drowsiness or lethargy, stupor, and coma.
269
what is REM sleep?
partially paralyzed so you dont move, allows the brain to analyse events or eliminate
meaningless information
270
what are meningies?
3 layers; (deep) pia mater, arachnoid mater, and dura mater.
271
what is CSF?
fluid found within the ventricles of the brain and surrounding the brain and spinal cord,
protects against impact damage, and is a delivery medium for nutrients and chemical signals.
272
what is the blood brain barrier?
helps maintain a protective environment for the brain.
tight junctions keep brain separated from many bloodborne substances.
3 layers; endothium in capillary walls, basla lamina around capillaries, astrocytes surround neurons
273
what is meningitis?
immflamuation of the meninges
274
what is the Arachnoid granulation villi ?
where CSF is reabsorbed
275
what are the 2 main functions of the spinal cord?
carries signals to and from brain and integration centre for reflexes
able to make its own decisions (reflex) if something happens fast enough it doesnt need
to check w the brain
276
how many nerves do you have in your spinal cord?
31 nerves
277
what are dorsal nerves for? ventral?
dorsal is sensory input, ventral is motor output
278
what is the cauda equina?
the point of transition between spinal cord to nerves
279
what is the ventral (anterior) median fissure and dorsal (posterior) median sulcus?
divides spine into left and right halves
280
what is the central canal in the spine?
runs thru the middles and filled w CSF
281
what are the dorsal and ventral horns in the spinal grey matter for?
dorsal- contains interneurons
ventral- contains cell bodies of somatic motor neurons
282
what is the grey commissure in the spinal cord?
connects masses of grey matter on either side
283
in the spinal cord, what allows for communication between the cord and brain?
white matter
284
what is flaccid and spastic paralysis?
flaccid- damage to the ventral root or ventral horn, nerve impulses are not transmitted to the skeletal muscles bc neurons are damaged
spastic- upper motor neurons of the primary motor cortex are damaged, voluntary control over skeletal muscle is lost.
285
what is paralysis and paraesthesia?
paralysis- loss of motor func
paraesthesia- loss of sensory func
286
what are the characteristics of neuronal pathways?
carry sensory and motor information to and from the brain.
2 going up and 3 going down
287
what is the Lateral spinothalamic tract?
lateral column of white matter, goes upwards from spine to thalamus, and is sensory.
288
how can you tell what a conductive nerve pathway is? example is Anterior (ventral) corticospinal tract.
lateral, anterior, posterior tells you where in the grey matter it is located in
the other of terms tells you which way the impulse is being carried (from cerebral cortex to spinal cord) which tells if its motor or sesnsory. ( sensory towards brain, motor away)
ex- anterior in white matter, going from cerebral cortex to spinal cord, a motor impulse
289
what are the 3 neurons in ascending sensory pathways?
1-unipolar, receptor to the spinal cord or brain stem
2- conducts the impulse to the thalamus.
3-thalamus- cerebral cortex
290
what are Spinocerebellar tracts?
convey information about muscle and tendon to cerebellum instead of thalamus
ipsilateral (dont cross over)
involve two neurons, not three.
291
what are descending pathways?
two neurons: upper motor neurons and lower motor neurons that innervate skeletal muscle.
292
what are direct descending pathways?
upper motor neurons from the cerebral cortex regulates fast, finely controlled or skilled movements.
293
what are indirect descending pathways?
upper motor neurons from the brainstem regulate muscles for balance and coarse movements and visual tracking
automatic skeletal musc movement like walking
294
what is included in the PNS?
sensory receptors, peripheral nerves and their associated ganglia, and efferent motor endings
295
what are non encapsulated dendritic endings
free nerve endings that detect temperature, pain, itch, light touch, or are located at the base of hair follicles
296
what are encapsulated dendritic endings?
consist of a dendrite enclosed in a connective tissue capsule and detect touch, initial, continuous, and deep pressure, and stretch of muscles, tendons, and joint capsules.
297
what are mechanoreceptors?
mech- stimulated by mechanical force, such as touch, pressure, vibration, and stretch.
298
what are chemoreceptors?
stimulated by chemicals, such as odours, tastes, or chemical components of body fluids.
299
what are thermorecpetors?
detect changes in temperature
300
what are photorecpetors?
detects light
301
what are nocieptorsceptors?
respond to painful stimuli
302
what are Exteroceptors
located at or near the body surface and detect stimuli from outside the body, such as touch, pressure, pain, skin temperature
303
what are Interoceptors
associated with internal organs and vessels, monitor chemical changes, stretch, or temperature
304
what are Proprioreceptors
found within skeletal muscles, joints, and associated connective tissues and relay information about body movements.
305
what is sensation
the awareness of changes in the internal and external environment.
306
what is perception
is the conscious interpretation of those stimuli.
307
what are 1st, 2nd, and 3rd order neurons
1- carry impulses from receptors
2-transmit to the cerebellum or third-order neurons
3-carry impulses to the postfrontal gyrus.
308
what is the phenomenon of referred pain
pain coming from a specific place but you feel it somewhere else ex is the heart
309
what is the function of pain
protects the body from damage
310
what is the pain tolerence? what is pain threshold?
tolerence- genetically determined, how much pain you can take
threshold- how intense a stimulus has to be in order to perceive pain
311
what is visceral pain
results from stimulation of receptors within internal organs from stimuli such as extreme stretch, chemical irritation, and muscle spasms.
312
what is a nerve?
a cord-like organ consisting of parallel bundles of peripheral axons enclosed by connective tissue wrappings.
313
what are the 3 layers in a nerve starting deepest?
endoneurium- thin layer of loose connective tissue that surronds the axon
Perineurium- connective tissue wrapping that bundles groups of fibres into fascicles.
Epineurium- wraps around nerve
314
what are dermatomes?
areas of skin innervated by cutaneous branches of a single spinal nerve. Most dermatomes overlap, so destruction of a single spinal nerve will not cause complete numbness.
315
The junctions between autonomic motor endings and the visceral effectors form what?
synapses en passant (“synapses in passing”)
316
what are Varicosities
Autonomic nerve fibres innervate most smooth muscle. these contractions are slower than skeletal
317
what is a ganglion?
collections of neuron cell bodies associated with nerves in the PNS.
318
what cells help regen nerves in PNS?
schwann cells
319
why cant nerves in the CNS regenerate?
oligodendrocytes have growth-inhibiting proteins that do not support regrowth of axons.
320
what is Chromatolysis?
the breakdown of Nissl bodies after nerve damage
321
what is wallerian degeneration?
the breakdown of the distal portion of the axon and myelin sheath.
322
Nerves within a regeneration tube grow at a rate of how much per day?
1mm
323
what is a reflex arc?
highly specific neural pathways that control reflexes
324
what are somatic reflexes?
affects skeletal musc, stretch reflexes, like when you hit the knee with the mallet
325
what are autonomic reflexes?
involve smooth muscle, cardiac muscle and/or glands. happens without you noticing like moving food from stomach to intestine
326
what is the autonomic nervous system
involuntary subdiv of the PNS,
It helps to maintain homeostasis by controlling smooth muscle, cardiac muscle and glands.
The ANS has parasympathetic and sympathetic divisions which cause opp affects
327
what is the somatic nervous system?
responsible for reflexes and for voluntary control over skel musc
328
what is sympathetic and parasympathetic?
sym- fight or flight, enables the body to cope with potential threats to homeostasis, by stimulating heart rate and force of contraction, increasing breathing, sweat production and inhibits not essential things like digestion
para- conserves energy, keeps body energy use as low as possible
329
what does testing a stretch reflex tell you about the PNS?
tells you hoe well it is responding to stimulus
330
what are the 5 components of a reflex arc?
1- receptor, responds to stimulus.
2- sensory or afferent neuron, enters dorsal root ganglion.
3- integration centre in grey matter, transfers info from sensory to motor neuron.
4- motor or efferent neuron in grey matter carries impulse into the ventral root to effector organ.
5- effector organ is musc or gland and reacts.
331
what is a post and preganglion nerve?
post- unmyelinated axon and carries the signal to an effector organ. releases norepinephrine
pre-terminates in a ganglion (outside of the CNS) where it synapses with the postganglionic neuron. releases acetylcholine
332
what neurotransmitter is released by the somatic NS? by the ANS? what coordinates these systems?
som- aceytlcohline, which is excitatory and causes contraction
ANS- aceytlcholine and epinephrine (aka adrenalin) and both can have either an excitatory or an inhibitory effect.
hypothalamus
333
what do Cholinergic neurons release? what are their 2 receptors?
-acetylcholine
-nicotinic (in post) and muscarinic (in para)
334
what is sympathetic and parasympathetic tone?
the rsult of having both active at the same time
sym- regulating systemic blood pressure
para- dominant in the heart, digestive system and urinary tracts, maintaining normal levels of function unless
overridden by the sympathetic system during stress
