Introduction to Cells Flashcards
1
Q
What is gamete formation and fertilization?
A
The process of generating gametes, fertilization, and the initial stages of embryonic development.
2
Q
What are basic anatomical terms used to describe directions in the human body?
A
Anterior, posterior, superior, inferior, dorsal, ventral, caudal, rostral.
3
Q
What are the different planes of the body?
A
Sagittal, transverse, frontal.
4
Q
What is gametogenesis?
A
The process of forming gametes through mitosis and meiosis.
5
Q
What is meiosis?
A
A type of cell division that reduces the chromosome number by half and results in the formation of haploid cells.
6
Q
What are spermatogenesis and oogenesis?
A
Processes of sperm and oocyte formation in males and females, respectively.
7
Q
What occurs during oogenesis?
A
Formation of a secondary oocyte and polar bodies through meiotic divisions.
8
Q
What are polar bodies?
A
Byproducts of the uneven division of cytoplasm during oogenesis and are not involved in reproduction.
9
Q
Where does fertilization occur?
A
In the ampulla of the uterine tube.
10
Q
What is the result of fertilization?
A
Formation of a zygote with a diploid number of chromosomes.
11
Q
What is blastocyst formation?
A
The process where the zygote undergoes cleavage to form a blastocyst, which implants into the uterine wall.
12
Q
What is gastrulation?
A
The process where the embryo forms three germ layers: ectoderm, mesoderm, and endoderm.
13
Q
What are epithelial tissues?
A
Derived from endoderm, ectoderm, and mesoderm; cover external and internal surfaces and line body cavities.
14
Q
What is the classification of epithelia based on cell shape?
A
Squamous, cuboidal, columnar.
15
Q
What is the classification of epithelia based on arrangement?
A
Simple (single layer) and stratified (multiple layers).
16
Q
What are the special types of epithelia?
A
Pseudostratified and transitional epithelia.
17
Q
What is epithelial cell polarity?
A
Epithelial cells exhibit distinct apical, lateral, and basal domains.
18
Q
What types of junctions connect epithelial cells?
A
Tight junctions, adhering junctions, desmosomes, hemidesmosomes, and gap junctions.
19
Q
What is the basement membrane?
A
A structure separating epithelial cells from underlying tissues, composed of the basal lamina and reticular lamina.
20
Q
What are exocrine glands?
A
Glands that release their products onto epithelial surfaces via ducts.
21
Q
What are the modes of exocrine secretion?
A
Merocrine, apocrine, holocrine.
22
Q
What defines merocrine secretion?
A
Involves exocytosis.
23
Q
What defines apocrine secretion?
A
Involves pinching off cytoplasm.
24
Q
What defines holocrine secretion?
A
Involves cell disintegration.
25
What is the role of cilia?
Involved in movement and composed of microtubules.
26
Where are cilia found?
In the trachea and uterine tube.
27
What is the function of microvilli?
Increase surface area for absorption.
28
Where are microvilli found?
In the intestinal epithelium.
29
What are stereocilia?
Similar to microvilli, found in specific locations like the epididymis and inner ear.
30
What happens during crossing over in meiosis?
Non-sister chromatids exchange genetic material.
31
True or False: The secondary oocyte completes the second meiotic division without fertilization.
False.
32
What are the three germ layers formed during gastrulation?
Ectoderm, mesoderm, endoderm.
33
What is the significance of the basement membrane?
Provides anchorage, filtration, and tissue organization.
34
What is the role of serosal membranes?
Secrete serosal fluid for lubrication and movement.
35
Fill in the blank: Epithelial tissues are _______ and highly mitotically active.
Avascular
36
What are cilia and where are they found?
Cilia are hair-like structures made of microtubules found in the trachea and uterine tube.
## Footnote
Cilia help move substances like mucus and oocytes.
37
What are microvilli and what is their function?
Microvilli are extensions of the cell membrane made of actin, increasing surface area for nutrient absorption in the intestines.
## Footnote
Found in the intestinal epithelium.
38
What are stereocilia and where are they located?
Stereocilia are long, non-motile extensions composed of cytoskeletal proteins and actin, found in the epididymis and inner ear.
## Footnote
They are involved in sperm maturation and sensory transduction.
39
What is the function of tight junctions?
Tight junctions prevent free passage of substances between cells.
## Footnote
They form a seal between adjacent cells.
40
What are adhering junctions and their types?
Adhering junctions include zonular adherence (belt desmosomes) and macular adherence (spot desmosomes).
## Footnote
They provide mechanical stability to tissues.
41
What are hemidesmosomes?
Hemidesmosomes connect cells to the basement membrane.
42
What is the role of gap junctions?
Gap junctions allow communication between cells through connexons.
43
What are the components of the basement membrane?
The basement membrane is composed of basal lamina and reticular lamina.
## Footnote
Basal lamina contains type 4 collagen and laminins, while reticular lamina contains type 3 collagen.
44
What are the functions of the basement membrane?
Functions include anchorage, filtration, and tissue separation.
45
What defines exocrine glands?
Exocrine glands have secretory portions and excretory ducts, classified as simple or branched based on duct structure.
46
What are the shapes of secretory portions in exocrine glands?
Secretory portion shapes include tubular and acinar.
47
What is merocrine secretion?
Merocrine secretion involves exocytosis of vesicles.
48
What characterizes apocrine secretion?
Apocrine secretion involves pinching off part of the cell.
49
What is holocrine secretion?
Holocrine secretion involves cell disintegration and release of contents.
50
What are connective tissues composed of?
Connective tissues are composed of an extracellular matrix, cells, and fibres.
51
What is mesenchyme?
Mesenchyme is the embryonic precursor for connective tissues, derived from the mesoderm.
52
What role do macrophages play in connective tissue?
Macrophages are phagocytic cells derived from monocytes and are abundant in connective tissues.
53
What are the main components of the extracellular matrix?
The extracellular matrix is composed of collagenous and non-collagenous proteins, including glycoproteins and proteoglycans.
54
What types of fibers are found in connective tissue?
Connective tissue fibres include collagen, elastic fibres, and reticular fibres.
55
What is the process of collagen synthesis?
Collagen synthesis begins in the rough endoplasmic reticulum of fibroblasts with the production of pre-procollagen, followed by hydroxylation, secretion, and aggregation into fibrils.
## Footnote
Vitamin C is crucial for hydroxylation of proline and lysine residues.
56
What are the main types of collagen?
The main types include:
* Type 1 (structural collagen)
* Type 2 (found in hyaline cartilage)
* Type 3 (reticular collagen)
* Type 4 (in basement membranes)
* Type 7 (anchoring collagen)
57
What is the structure and function of the basement membrane?
The basement membrane provides a physical connection between epithelium and underlying tissue, limiting epithelial growth and serving as a diffusion site for nutrients and waste.
58
What are elastic fibers made of?
Elastic fibres are composed of tropoelastin, fibrillins, and fibulin.
## Footnote
Desmosine allows cross-linking for stretch and recoil properties.
59
How are connective tissues classified?
Connective tissues can be classified as loose or dense.
60
What characterizes dense connective tissue?
Dense connective tissue is characterized by a high density of collagen fibres.
61
What role does adipose tissue play?
Adipose tissue is specialized connective tissue involved in fat storage and metabolism, with endocrine functions.
62
What is the composition of bone tissue?
Bone tissue includes a matrix composed of type 1 collagen fibres and various bone cells.
63
What are the segments of long bones?
Long bones can be divided into epiphysis, metaphysis, and diaphysis.
64
What types of bone cells exist?
Bone cells include osteoprogenitor cells, osteoblasts, osteocytes, and osteoclasts.
65
What is bone remodelling?
Bone remodelling is a dynamic process involving continual bone resorption and deposition.
66
What is osteogenesis imperfecta?
Osteogenesis imperfecta is a genetic disorder caused by a defect in collagen genes, leading to brittle bones.
67
What regulates bone remodelling?
Bone remodelling is regulated by two major pathways involving RANK/RANK-L and macrophage colony-stimulating factor.
68
What are the processes of bone formation?
Bone formation occurs through intramembranous and endochondral ossification.
69
What is the process involving continual bone resorption and deposition?
Bone remodelling
## Footnote
It maintains a balance between osteoclast and osteoblast activity.
70
What genetic disorder is characterized by brittle bones prone to fractures?
Osteogenesis Imperfecta
## Footnote
Caused by a defect in collagen genes.
71
Which two major pathways regulate bone remodelling?
* RANK/RANK-L pathway
* Macrophage colony-stimulating factor
72
What are the two processes of bone formation?
* Intramembranous ossification
* Endochondral ossification
73
What can cause bone disorders?
* Genetic defects
* Metabolic imbalances
* Dietary deficiencies
74
What is the function of cartilage in the skeletal system?
It plays a crucial role in movement and bone tissue development.
75
How many types of cartilage are there, and what are they?
* Hyaline cartilage
* Elastic cartilage
* Fibrocartilage
76
What is articular cartilage, and how is it affected in osteoarthritis?
It is a type of hyaline cartilage that provides a smooth surface for joint movement and is degenerated in osteoarthritis.
77
What are the main components of bone tissue?
* Type 1 collagen fibres
* Osteoblasts
* Osteocytes
* Osteoclasts
78
What is the epiphysis in long bones?
The end part of a long bone, covered with articular cartilage.
79
What is the role of osteoprogenitor cells?
They are stem cells that give rise to osteoblasts.
80
What do osteoclasts do?
They are responsible for bone resorption.
81
Which pathway stimulates osteoclast differentiation?
RANK/RANK-L pathway.
82
What is the difference between plasma and serum?
Plasma contains fibrinogen, while serum is plasma without fibrinogen.
83
What is erythropoiesis?
The process of red blood cell production.
84
What type of muscle is attached to bones via tendons?
Skeletal muscle.
85
What is the main characteristic of cardiac muscle?
It is involuntary and striated.
86
What type of muscle is found in hollow organs?
Smooth muscle.
87
What are the unique features of cardiac muscle cells?
* Intercalated discs
* Desmosomes
* Gap junctions
88
What is muscle hypertrophy?
The increase in muscle size due to an increase in myofilament content.
89
What causes pathological muscle atrophy?
* Damage to motor nerves
* Disuse
* Diseases affecting skeletal proteins
90
What is the role of platelets in the blood?
They are crucial for the blood clotting process, known as haemostasis.
91
What is the function of leukocytes?
They are involved in immune responses.
92
What type of connective tissue is blood classified as?
A special type of connective tissue.
93
Fill in the blank: The matrix of bone tissue includes type 1 collagen fibres known as _______.
osteoid
94
What is one consequence of a lack of gravity on bone density?
Decreased osteoblast activity.
95
What type of muscle is involuntary, striated, and branched?
Cardiac muscle
## Footnote
Cardiac muscle features intercalated discs that contain desmosomes and gap junctions.
96
What is the regenerative capacity of cardiac muscle cells?
Limited
## Footnote
Damage leads to necrosis and scar tissue formation, reducing contractile function.
97
What are the characteristics of smooth muscle?
Non-striated, involuntary, found in hollow organs
## Footnote
Contracts slowly and rhythmically, regulated by the autonomic nervous system and hormones.
98
How does smooth muscle contraction occur?
Calcium binds to calmodulin, activating myosin light chain kinase
## Footnote
This phosphorylates myosin, allowing interaction with actin.
99
What are the three types of muscle tissue?
* Skeletal
* Cardiac
* Smooth
100
Skeletal muscle is attached to bones via _______.
tendons
101
What is the primary function of skeletal muscle?
Facilitates voluntary movement and posture
## Footnote
Also involved in protection and thermoregulation.
102
Where is cardiac muscle located?
In the heart
103
What is the primary function of cardiac muscle?
Pumps blood
104
What type of muscle lines hollow organs and tubes?
Smooth muscle
105
What is the term for the contraction process in smooth muscle?
Peristalsis
106
What are myoepithelial cells?
Cells that contract in response to hormones like oxytocin
## Footnote
They facilitate milk release in the mammary gland.
107
What is the structure of muscle composed of?
Bundles called fascicles
108
What is the outermost layer covering the entire muscle?
Epimysium
109
Skeletal muscle cells originate from _______.
mesenchymal cells
110
What do myoblasts fuse to form?
Myotubes
111
What is the contractile unit of muscle fibers?
Sarcomeres
112
What is required for myosin head movement and detachment during muscle contraction?
ATP
113
What does the sarcoplasmic reticulum store?
Calcium
114
What role do T-tubules play in muscle contraction?
Transmit depolarization signals to the sarcoplasmic reticulum
115
What are satellite cells?
Myogenic stem cells involved in muscle regeneration
116
What is muscle hypertrophy?
Increase in muscle cell size
117
What occurs during muscle atrophy?
Decrease in muscle cell size
118
What type of atrophy occurs when muscles are not used?
Disuse atrophy
119
What is the role of microglia in the CNS?
Resident immune cells capable of phagocytosis
120
Astrocytes are abundant glial cells that form the _______.
blood-brain barrier
121
What is the primary function of oligodendrocytes?
Form myelin sheaths in the CNS
122
What do Schwann cells do?
Myelinate axons in the peripheral nervous system
123
What do ependymal cells line?
Ventricular cavities of the brain and central canal of the spinal cord
124
What are the basic functional units of the nervous system?
Neurons
125
What is the difference between electrical and chemical synapses?
* Electrical synapses: direct ion movement
* Chemical synapses: use neurotransmitters
126
What are the types of neurons?
* Multipolar
* Bipolar
* Pseudounipolar
127
What does myelination do for nerve conduction?
Increases speed
128
What are the connective tissue layers surrounding peripheral nerves?
* Epineurium
* Perineurium
* Endoneurium
129
What is the function of oligodendrocytes?
Oligodendrocytes myelinate several axons in the central nervous system
## Footnote
Myelination increases the speed of nerve impulse conduction.
130
What is the role of ependymal cells?
Ependymal cells are essential for cerebrospinal fluid formation and contribute to the CSF blood barrier
## Footnote
They have microvilli for absorption and cilia for circulating cerebrospinal fluid.
131
What do dendrites do?
Dendrites receive synaptic inputs from other neurons
132
What is the primary function of axons?
Axons conduct impulses and can be myelinated or unmyelinated
133
What is axonal transport?
Axonal transport is essential for moving neurotransmitters and nutrients
134
What are Purkinje neurons known for?
Purkinje neurons have extensive dendritic trees and form about 100,000 synaptic connections
135
What type of synapse is most common?
Chemical synapses are the most common type
136
True or False: Electrical synapses are common in the nervous system.
False
137
What connects electrical synapses?
Electrical synapses are connected by gap junctions
138
What is a characteristic of chemical synapses?
Chemical synapses use neurotransmitters packed in synaptic vesicles
139
Fill in the blank: Multipolar neurons have ______ axon and many dendrites.
one
140
What is the role of myelin?
Myelin increases membrane resistance and decreases capacitance
141
What are the three layers of peripheral nerve structure?
* Epineurium
* Perineurium
* Endoneurium
142
What is the function of nodes of Ranvier?
Nodes of Ranvier are sites of action potential generation
143
True or False: Chemical synapses allow for bi-directional signaling.
False
144
What type of neurons have a single axon that branches into two?
Pseudounipolar neurons
