tissues Flashcards
1
Q
what does the maintenance of life involve?
A
Maintaining boundaries
Movement
Responsiveness
Digestion
Metabolism
Excretion
Reproduction
Growth
2
Q
what do we mean by “maintaining boundaries”?
A
Separation between internal and external environments must exist
Plasma membranes separates cells
Skin separates organism from environment
3
Q
why do humans need movement?
A
Muscular system allows movement
1) of body parts via skeletal muscles
2) of substances via cardiac muscle (blood) and smooth muscle (digestion, urination)
4
Q
what is contractility?
A
refers to movement at the cellular level
5
Q
what is responsiveness? give a few examples
A
Ability to sense and respond to stimuli
ex: Withdrawal reflex prevents injury
Control of breathing rate, which must change in response to different activities
6
Q
what is digestion?
A
Breakdown of ingested foodstuffs, followed by absorption of simple molecules into blood
7
Q
what is metabolism?
A
All chemical reactions that occur in body cells
Sum of all catabolism (breakdown of molecules) and anabolism (synthesis of molecules)
8
Q
what is catabolism?
A
(breakdown of molecules)
9
Q
what is anabolism?
A
synthesis of molecules
10
Q
what is excretion?
A
Removal of wastes from metabolism and digestion
11
Q
do anabolic reactions require energy?
A
yes
12
Q
do catabolic reactions require or release energy?
A
release
13
Q
what are the different types of excretions?
A
Urea (from breakdown of proteins and nucleic acids), carbon dioxide (from metabolism), feces (unabsorbed foods)
14
Q
what are the different types of reproduction?
A
At the cellular level, reproduction involves division of cells for growth or repair
At the organismal level, reproduction is the production of offspring
15
Q
what is growth?
A
Increase in size of a body part or of organism
16
Q
what are the 11 organ systems that work together to maintain life?
A
-respiratory
-integumentary
-skeletal
-muscular
-nervous system
-endocrine system
-cardiovascualr system
-lymphatic system
-digestive system
-urinary system
-male reproductive system
-female reproductive system
17
Q
what is homeostasis?
A
Homeostasis is the maintenance of relatively stable internal conditions despite continuous changes in environment
18
Q
what are variables in homeostasis?
A
Variables are factors that can change (blood sugar, body temperature, blood volume, etc.). A dynamic state of equilibrium, always readjusting as needed
19
Q
what is interstitial fluid? what does it do?
A
The internal environment of vertebrates is called the interstitial fluid (ISF).
It exchanges nutrients and wastes with blood contained in microscopic vessels called capillaries.
20
Q
what is the PH of blood/interstitial fluid in the body?
A
Our bodies control the pH of our blood and interstitial fluid to within a tenth of a pH unit of 7.4.
21
Q
what are the processes of homeostasis?
A
1) stimulus (produces change in variable)
2) receptor (detects change)
3)input (information sent along afferent pathway to control center)
4) output (information sent along efferent pathway to effector)
5) responses (of effector feeds back to reduce the effect of stimulus and returns variable to homeostatic level
22
Q
what is the most used feedback mechanism in the body?
A
negative feedback
23
Q
what is negative feedback inhibition?
A
Response reduces or shuts off original stimulus
Variable changes in opposite direction of initial change
24
Q
what does negative feedback inhibition allow for?
A
this prevents small changes from becoming too large
25
what are examples of negative feedback inhibition?
-regulation of body temperature
-regulation of blood glucose
26
27
How does sweating work
28
what is positive feedback?
Response enhances or exaggerates the original stimulus (not homeostasis)
29
How does insulin work
30
give two examples of positive feedback inhibition?
1) Enhancement of labor contractions by oxytocin
2) Platelet plug formation and blood clotting
31
explain positive feedback inhibition for childbirth
During childbirth, the pressure of the baby’s head against opening of the uterus stimulates uterine contractions.
These cause greater pressure against the uterine opening, heightening the contractions, which cause still greater pressure.
Positive feedback brings childbirth to completion (not maintenance of a steady state).
32
33
How does platelet formation work
34
what are some major changes, that are programmed to happen?
1) puberty and pregnancy.
2) hormone levels responsible for the menstrual cycle
3) the human body reacts to certain infections by raising the set point for temperature to a slightly higher level, and the resulting fevers helps fight infection.
35
what is the point to having body cavities?
Body contains internal cavities that are closed to environment
Cavities provide different degrees of protection to organs within them
36
what are the two sets of body cavities?
dorsal body cavity (back)
ventral body cavity (stomach)
37
what's in the dorsal body cavity (two subdivisions)?
-cranial cavity
-vertebral cavity
38
what is the point of the dorsal body cavity?
Protects fragile nervous system
39
what are the subdivisons to the ventral body cavity?
-thoracic cavity
-abdominopelvic cavity
40
what's in the thoracic cavity?
-plural (lungs)
-pericardial (heart)
41
what is the viscera?
internal organs in the ventral body cavity
42
what are organs in the ventral body cavity held by?
mesenteries
43
what are mesenteries
sheets of connective tissues called mesenteries in body cavities moistened or filled with fluid. attaches to body wall
44
what are tissues?
Tissues are groups of cell with a common structure and function.
45
how are tissues held together?
A tissue may be held together by a sticky extracellular matrix that coats the cells or weaves them together in a fabric of fibers.
46
what are the categories of tissues?
-epithelial
-connective
-nervous
-muscle tissue
47
what is epithelial tissue?
Epithelial tissue occurs in sheets of tightly packed cells, covers the outside of the body and lines organs and cavities.
48
how are epithelial cells so closely riveted together?
Cells of an epithelium are closely joined
- may be riveted together by tight junctions.
49
why doe epithelium need to be highly revised together?
if not tightly packed, since line organs, there could be fluid mix (ex: urine and blood)
50
what are the two main forms of epithelium?
Covering and lining epithelia: on external and internal surfaces (ex: skin)
Glandular epithelia: Secretory tissue in glands (ex: salivary glands)
51
can epithelium be both lining and glandular?
yes!
52
what does epithelial tissue do?
Epithelial tissue functions as a barrier protecting against:
mechanical injury
invasive microorganisms
fluid loss.
53
what are the two types of epithelial cell surfaces?
apical and basal
54
what is an apical surface?
upper free side, is exposed to surface or cavity (air or fluid)
55
true or false, all apical surfaces are smooth?
false. Most apical surfaces are smooth, but some have specialized fingerlike projections called microvilli
56
what is a basal surface?
lower attached side, faces inwards toward body
57
what does the basal surface attach to?
basal lamina
58
what is the basal lamina?
an adhesive sheet that holds basal surface of epithelial cells to underlying cells, is a thin layer of extracellular matrix that lies between epithelial cells and their underlying tissues.
59
what is the basal lamina composed of?
It is composed of collagen and other filaments embedded in proteoglycans.
60
what is another word for basal lamina?
basement membrane
61
how are epithelia classified?
Epithelia are classified by the number of cell layers and the shape of the cells on the free surface.
62
what is simple epithelium? what is it involved in?
has a single layer of cells
- involved in absorption, secretion, or filtration processes
63
what are the different types of shapes of epithelium cells?
-squamous
-cuboidal
-columnar
64
what does a squamous cell look like?
nucleus squished like cell
65
what does cuboidal cell look like?
cubelike shape, with round nucleus
66
what does a columnar cell look like?
nucleus non-circular and more towards bottom
67
what are the two types of epithelium layers?
simple and stratified
68
what is stratified epithelium?
has multiple tiers of cells.
- more durable than simple epithelia because protection is the major role
69
what is the role of stratified epithelium?
durability/protection
70
where is pseudo stratified epithelium found?
trachea
71
what is pseudo stratified epithelium?
looks stratified, only because the nucleus of different cells are at different levels, but not many cell layers its just an illusion
72
what does simple squamous epithelium do? where is it found?
cells are flattened laterally, and cytoplasm is sparse
- where rapid diffusion is priority
-kidney, lungs, heart, blood vessels, lymphatic vessels, lining of ventral body cavity
73
what does Simple cuboidal epithelium do? where is it found?
Single layer of cells
Involved in secretion and absorption
Forms walls of smallest ducts of glands. FILTRATION
found in kidney tubules, ducts and secretory portions of small glands, ovary surface.
74
what is simple columnar epithelium?
single layer of tall, closely packed cells
Some have microvilli, some have cilia
Some contain mucus-secreting goblet cells (the cilia help to move mucus)
- involved in absorption, secretion of enzymes and mucus
75
what is the difference between microvilli and cilia?
Cilia are longer and thicker than microvilli. Cilia can move while microvilli cannot. Cilia look more like hairs, while microvilli are folded cell membranes.
76
where do u find simple columnar epithelium?
non ciliated type: found in digestive tract, gallbladder
ciliated type: found in small bronchi and fallopian tubes
intestines
77
what is pseudostratified columnar epithelium?
Cells vary in height and appear to be multi-layered and stratified, but tissue is in fact single-layered simple epithelium
Many cells are ciliated
Involved in secretion, particularly of mucus, and in movement of mucus via ciliary sweeping action. Mucus also traps dust and particles.
78
where is pseudo stratified columnar epithelium found?
- mostly in upper respiratory tract (trachea) and tubules in testes
79
what is the most widespread of stratified epithelia?
stratified squamous
80
what is stratified squamous epithelium?
Free surface is squamous, with deeper cuboidal or columnar layers
Located in areas of high wear and tear (example: skin, mouth, vagina, anus)
81
what are the two types of stratified squamous epithelium?
- keratinized type found in skin;
- nonkeratinized type found in moist linings
82
what is stratified cuboidal epithelium?
Quite rare
Found in some sweat and mammary glands
Typically only two cell layers thick
83
what is glandular epithelia?
absorb or secrete chemical solutions
84
what does glandular epithelia in the thyroid gland do?
Glandular epithelia in the thyroid gland secrete a hormone that regulates fuel consumption.
85
what does the glandular epithelia that line the digestive and respiratory tracts do?
form a mucous membrane that secretes mucus.
86
what does mucus do?
lubricates the surface and keeps it moist
87
what is connective tissue?
functions mainly to bind and support other tissues
88
what does connective tissue contain?
- contains a sparse population of cells scattered through an extracellular matrix.
89
what is the extracellular matrix?
Matrix generally consists of a web of fibers embedded in a uniform foundation that may be liquid, jellylike, or solid.
90
what secretes the matrix for connective tissue?
the connective tissue cells usually secrete the matrix.
91
what are the major functions of connective tissue?
binding and support, protecting, insulating, storing reserve fuel, and transporting substances (blood)
92
what are the 3 kind of connective tissue fibres?
-collagenous fibers
-elastic fibers
-reticular fibers
93
what are collagenous fibers?
made of collagen, non-elastic and do not tear easily when pulled lengthwise.
94
what are elastic fibers?
long threads of elastin and provide a rubbery quality
95
what are reticular fibers?
very thin and branched, composed of collagen and form a tightly woven fabric that joins connective tissue to adjacent tissues.
96
what are the cells in the connective tissue that secrete the ECM? where are they found?
Fibroblasts found in connective tissue
Chondroblasts found in cartilage
Osteoblasts found in bone
97
true or false, 3 kinds of connective tissue fibers are all proteins?
true!
98
what are blast cells?
Immature form of cell that actively secretes the components of the matrix
99
what is a cyte cell?
Mature, less active form of “blast” cell that now becomes part of and helps maintain health of matrix
100
what are the major types of connective tissue in vertebrates?
loose connective tissue (also called areolar)
adipose tissue
fibrous (dense) connective tissue
cartilage
bone
blood
101
what does loose connective tissue function as?
binds epithelia to underlying tissues and functions as packing material, holding organs in place.
102
which types of fibre does loose connective tissue have?
all three
103
what are the cells in the loose connective tissue?
a) Fibroblasts: secrete the protein ingredients of the extracellular fibers.
b) Macrophages: amoeboid cells that roam the maze of fibers, engulfing bacteria and the debris of dead cells by phagocytosis.
c) Mast cells: mediate inflammatory responses such as allergic reactions
104
what does adipose tissue do?
stores fat in adipose cells distributed throughout the matrix
- pads and insulates the body and stores fuel as fat molecules.
- Each adipose cell contains a large fat droplet that swells when fat is stored and shrinks when the body uses fat as fuel.
105
what is fibrous/dense connective tissue?
- fibers organized into parallel bundles to maximize nonelastic strength.
Very high tensile strength; can withstand high tension and stretching
Closely packed bundles of thick collagen fibers run parallel to direction of pull
106
where is fibrous connective tissue found?
-tendons: attaching muscles to bones
-ligaments: joining bone to bone
107
what is cartilage?
Cartilage has an abundance of collagenous fibers embedded in a rubbery matrix made of chondroitin sulfate (a protein-carbohydrate complex).
108
what is chondroitin sulfate?
a protein carbohydrate complex
109
what do chondroblasts secrete?
collagen and chondroitin sulfate
110
what are chondrocytes? what do they allow for?
These molecules also make up part of the extracellular matrix (ECM) of animal cells
Chondrocytes found in cavities called lacunae and they maintain and nourish the extracellular matrix.
111
what is cartilage composed of?
Cartilage is 80% water, with packed collagen fibers and glycoproteins (chondroitin and hyaluronic acid)
112
what are the two glycoproteins found in cartilage?
chondroitin and hyaluronic acid
113
what type of material is cartilage?
cartilage is a strong yet somewhat flexible support material
114
where is cartilage found?
Cartilage found in nose, ears and vertebral disks.
115
what is the ECM composed of?
The ECM is a complex of glycoproteins and other carbohydrate -containing molecules secreted by cells. It contains collagen, proteoglycans, fibronectin and integrins.
116
which connective tissue is mineralized?
bones
117
what are the two types of osteo cells in bone?
Osteoblasts deposit a matrix of collagen.
Osteocytes maintain the matrix
118
where do the osteocytes and osteoblasts of bones reside?
in lacunae (cavities in matrix)
119
why is bone said to be mineralized?
calcium, magnesium, and phosphate ions combine and harden within the matrix into the mineral hydroxyapatite
120
what is the relationship between bone and cartilage?
bone is harder than cartilage without being brittle.
121
what are the microscopic units of mammalian bones that keep repeating?
osteons
122
what are osteons?
Osteon contains concentric layers of mineralized matrix deposited around a central canal containing blood vessels and nerves.
123
true or false, blood has an extracellular matrix?
true
124
what is the matrix of blood?
plasma, and its made of:
- water
- salts
- variety of dissolved proteins
125
what are the cells suspended in plasma?
-erythrocytes
-leukocytes
-platelets
126
what are erythrocytes?
(red blood cells) which carry oxygen
127
what are leukocytes?
(white blood cells) which function in defense against viruses, bacteria, and other invaders
128
what are platelets?
cell fragments which aid in blood clotting
129
what are nervous tissues?
Nervous tissue senses stimuli and transmits signals from one part of the animal to another.
130
what is the functional unit of nervous tissue?
neuron, or nerve cell which consists of a cell body and two or more extensions, called dendrites and axons.
131
what is the neuron composed of?
cell body and two or more extensions called dendrites and axons
132
what are dendrites?
Dendrites transmit nerve impulses from their tips toward the rest of the neuron.
133
what are axons?
Axons transmit impulses toward another neuron or toward an effector, such as a muscle cell.
134
what are the three types of glia supporting cells?
-astrocytes (surround neurons, keep them tight like tight junction)
-schwann: makes myelin for peripheral nervous system
-digodendrocytes: makes myelin for central nervous system
135
what is muscle tissue composed of?
Muscle tissue is composed of long cells called muscle fibers that are capable of contracting when stimulated by nerve impulses.
136
what's in the cytoplasm of muscle fibre cells?
Myofibrils
137
what are myofibrils composed of?
actin and myosin
138
what is the most abundant tissue in most animals?
muscle
139
what accounts for the most energy consuming cellular work?
muscle contractions
140
what are actin and myosin?
proteins that lead to muscle contraction
141
what are the three types of muscle tissue?
skeletal muscle
cardiac muscle
smooth muscle
142
how is skeletal muscle attached to bones?
tendons
143
which muscle tissue is responsible for voluntarily movement?
skeletal
144
what is another word for skeletal muscle?
striated
145
give the characteristics of skeletal muscle?
Skeletal muscle also called striated muscle because the overlapping filaments give the cells a striped (striated) appearance.
Cells are called muscle fibers
Contain multiple nuclei
146
where is cardiac muscle found?
contractile wall of the heart.
147
what are the characteristics of cardiac muscle?
It is striated like skeletal muscle, but cardiac cells are branched.
148
how are the ends of the cardiac muscle cells put together?
The ends of the cells are joined by intercalated disks, which relay signals from cell to cell during a heartbeat.
149
what does smooth muscle lack?
striations
150
where is smooth muscle found?
is found in the walls of the digestive tract, urinary bladder, arteries, and other internal organs, works involuntarily
151
what is the difference between skeletal and smooth muscle?
Contracts more slowly than skeletal muscles but can remain contracted longer.
152
what are the shapes of the nucleus of smooth muscle
Cells are spindle-shaped, with one nucleus
153
what are examples of smooth muscle use?
churning of the stomach and constriction of arteries
154
which cells have a nucleus with a corkscrew appearance?
smooth muscle
155
how are the tissues organized in layers in some organs?
in multiple
156
what are the vertebrates stomach layers?
1) Thick epithelium lines the lumen and secretes mucus and digestive juices.
2) Outside this layer is a zone of connective tissue.
3) Then there are three layers of smooth muscle. The first layer is oblique, the second is circular and the third is longitudinal.
4) Another layer of connective tissue (serosa) encapsulates the entire stomach.
157
what is the peritoneum?
the membrane that forms the lining of the abdominal cavity
- covers most of the intra-abdominal organs, and is composed of a layer of mesothelium (epithelium) supported by a thin layer of connective tissue.
158
what is the link between the digestive track and circulatory system?
Nutrients absorbed from the digestive tract are distributed throughout the body by the circulatory system.
159
what is the link between the heart, the circulatory system and the respiratory system?
Heart that pumps blood through the circulatory system depends on nutrients absorbed by the digestive tract and on oxygen obtained by the respiratory system.
160
what is the difference between mesenteries and peritoneum?
mesenteries: stick to the back of cavity
peritoneum: lining
161
how does exchange with the environment happen in the body?
occurs as dissolved substances diffuse and are transported across the plasma membranes between cells and aqueous surroundings
162
what does the circulatory system do?
shuttles material among all the exchange surfaces within the animal.
163
