lecture 1 Flashcards
What are cells
The smallest living entity and building blocks of the body
What are tissues
what are the 4 types of tissues
Tissues are made of cells of similar structure and function
The 4 types are epithelial, connective, muscle, and nervous tissues
What are organs
Organs consist of at least 2 primary tissues, and each tissue serves different function
What is a system
Systems are organs that are located in different regions of the body and perform related functions
Epithelial tissues are made of ___ arranged in ___ sheet or in a column
(copy qn and fill in the blanks)
Epithelial tissues are made of epithelium arranged in continuous sheet or in a column
Name the 3 types of epithelial tissue
define simple and stratified arrangement of epithelial tissue
Squamous, cuboidal, columnar
simple: one cell layer thick, specialised for transport
stratified: Composed of a number of layer (multiple layers), specialised for protection
Characteristics and function of squamous epithelium, where are these tissues commonly found
(the thickness of the epithelial tissue depends on its function)
Flattened with a prominent, protruding nucleus for diffusion and filtration, lines the oral cavity, pulmonary alveoli and the glomerulus of the kidney
Characteristics and function of cuboidal epithelium, where are these tissues commonly found
(the thickness of the epithelial tissue depends on its function)
Cube-shaped for absorption, secretion, and excretion, lines the kidney tubule, salivary and pancreatic ducts
Characteristics and function of columnar epithelium, where are these tissues commonly found
(the thickness of the epithelial tissue depends on its function)
Tall column shaped cells for absorption, secretion, and excretion, lines the digestive tract and uterine tubes
Epithelial tissues are always anchored to a connective tissue, why is it important for the epithelial tissue to anchor to connective tissue?
Epithelial tissues are avascular (have no blood vessels) while connective tissues are highly vascular. Thus, the connective tissues provides essential nutrients to the epithelial tissues
What is the name of the surface of the epithelial tissue that is anchored to the connective tissue?
Basement membrane
Name the 2 laminas of the basement membrane and the cell that secrets their main components
Basal lamina contains collagen, laminin, proteoglycan, glycoproteins, etc secreted by the epithelial cells
reticular lamina rich in collagen fibers secreted by fibroblasts (connective tissue cells)
Positions/sides
apical surface/apical layer/luminal
basal surface - connected to the ___ membrane
lateral surface - connected by ___ junctions, ___ junctions, ___ junctions (surface where 2 adjacent cells touch)
(copy qn and fill in the blanks)
Positions/sides
apical surface/apical layer/luminal
basal surface - connected to the basement membrane
lateral surface - connected by tight junctions, adherens junctions, gap junctions (surface where 2 adjacent cells touch)
What are the 2 types of connective tissues
Connective tissue proper and special connective tissue
Name and describe the 2 different types of connective tissue proper
Loose - more cells, less protein fibers
Dense - mostly densely packed collagen fibers and fewer cells (mainly fibroblasts)
Why are the special connective tissues also considered a connective tissue, and what are the examples of special connective tissues?
They all contain protein fibers and cells
cartilage, bone, blood
Components of cells in the connective tissues
Fibroblasts (most common cell in the connective tissue), adipocytes (fat cells), macrophages, plasma cells, mast cells (produce heparin and histamine), infiltrated white blood cells (during inflammation)
Components of matrix in the connective tissues
Protein fibers: collagen(strong and flexible), elastin (stretchable, makes tissue elastic), reticulin (thin collagen fibers coated with glycoproteins)
Ground substances: water and a variety of small and large molecules (soluble molecules)
What are the functions of the connective tissues (got 6)
Connects cells and organ together to form a network or lattice in organs
Provides strong flexible support/elasticity to tissues
Stores “body fluid” and nourishes the cells and organs
Fill spaces, store fat, and provide cushion (adipose tissue)
Site of immune response
Involved in wound healing, tissue remodeling, cancer metastasis, and more as it provides a stem cell niche (an environment for stem cells to thrive)
Types of muscle tissues
Long striated cells with multiple nuclei
Branching, striated cells, fused at plasma membranes
Long spindle-shaped cells, each with one nucleus; mainly located in internal hollow organs
Define homeostasis
Homeostasis is the maintenance of stable conditions of the internal environment (maintain constant internal environment)
*maintains dynamic constancy for cell survival
What are the homeostatic conditions (got 7)
Concentration of nutrients
Concentration of waste products
Concentration of O2 and CO2
Concentration of salt and electrolytes
pH
Temperature
Volume and pressure
*Must maintain the dynamic constancy of the homeostatic conditions for cells to survive
What are the 2 types of homeostasis regulation
Intrinsic control: being regulated within the organ (outside factors like endocrine and nervous systems does not affect)
Extrinsic control: regulatory mechanism initiated outside the organ alters the activity of the organs, accomplished by endocrine and nervous systems
What are the 3 types of controls (just the name)
Negative feedback (most common), positive feedback, feed-forward
Explain negative feedback and the components of negative feedback
The change in a controlled variable (any of the homeostatic conditions) triggers a response that opposes change, driving the variable in the opposite direction of the initial change
Sensor -> Afferent pathway -> Integrating Centre -> Efferent pathway -> Effector
-the effector will respond by going against the change (if body temp decreases, effectors will respond by increasing body temp back to the set point)
Explain positive feedback
The change in a controlled variable is further enhanced by the regulatory system so that the controlled variable continue to be moved in the direction of the initial change
It accelerates the resolution of a process which has already started
-eg during childbirth: the first contraction leads to an increase in oxytocin production which in turn progressively heightened uterine contraction , which then leads to more oxytocin production. The cycle continues until the child is born.
Explain feed-forward
The change occurs in anticipation of a change in a controlled variable
-When food is digested, fatty acids and glucose stimulates the intestinal endocrine cells (enteroendocrine cells) to release glucose-dependent insulinotropic peptide (GIP), which relays signals to B-cells in pancreas to produce insulin to prepare for glucose and fatty acid absorption. The feed-forward control ensures that insulin is present in the bloodstream before the fatty acids and glucose are absorbed into the bloodstream to aid in the absorption of fatty acids and glucose by the muscle cells for storage
Characteristics of the epidermis (topmost layer of the skin)
The epidermis have stratified epithelial cells (avascular)
The inner layer rapidly divides while the outer layer is flattened and dead (keratinized)
Contains melanocytes and immune cells like keratinocytes, langerhans cells, and Granstein cells
Characteristics of the dermis
Mainly contains irregular dense connective tissues, is rich in collagen and elastin fibers, blood vessels and nerve endings
Characteristics of the hypodermis
Subcutaneous tissue
Loose layer of connective tissue, where most fats in the body are stored
The relationship between stratum basale, stratum spinosum/granulosum/lucidum, and stratum corneum of the epidermis
Stratum basale is derived from the stem cells, where new cells develop in the deepest layer of the epidermis. This layer contains keratinocytes
The newly developed cells are differentiated to form the stratum spinosum/granulosum/lucidum
The stratum corneum is a layer of keratinized cells, making it tough and non-permeable. All cells have died at the stratum corneum layer
The further the cells are pushed from the dermis, the less access they have to the nutrients in the internal environment as the epidermis layer is avascular
Why is the hypodermis/subcutaneous tissue layer the most preferred site for injection?
Compared to the epidermis, there is more blood vessels for the injected liquids to be transported away from the injection site to the rest of the body
Compared to the dermis, there is less blood vessels to ensure that the injected liquids are not absorbed too quickly, making it more effective for drugs to be injected into the hypodermis layer
There is also more cushion provided by the adipose cell
Function of the skin (got 4)
Protection: skin barrier impedes passage of most materials into the body
Participate in immune response: keratinocytes produce inflammatory cytokines and kill microbes. langerhans and granstein cells serve as antigen-presenting cells (APC), connective tissues in dermis and hypodermis are important sites for immune response
Production of melanin by melanocytes in the epidermis
Temperature regulation
What are the normal body temperatures
Core temperature - taken from inner tissue (mouth/anus): constant
Skin temperature: fluctuates depending on the ambient temperature
How does heat input occur?
From internal heat productions like metabolism and shivering, and from the transfer of heat from the external environment to our body through radiation and conduction
How does heat output occur?
From body mechanism of sweating, which leads to evaporation and from the transfer of body heat to the external environment by convection and radiation
What are the 2 main systems in the Neural system?
The Central Nervous System (CNS) and the Peripheral Nervous System (PNS)
What does the afferent divisions of the neural system do?
The afferent division transmits impulses from the peripheral organs to the CNS
Receptors in the internal organs like the sensory receptors (like thermoreceptors) (in eyes, nose, mouth, and nose too) and the visceral receptors (eg enteroendocrine cells)
What does the efferent division of the neural system do?
The efferent division transmits impulses from the CNS to the peripheral organs
State the difference between the somatic nervous system and the autonomic system
The somatic nervous system is associated with voluntary control of body movement and reflex arcs (transmits impulses to the skeletal muscle to invoke voluntary action)
The autonomic nervous system regulates involuntary physiologic processes (transmit impulses to the smooth/cardiac muscles, exocrine glands, some endocrine glands, and the digestive organs to invoke involuntary actions)
___ regulates body temperature based on the ___ ___
(copy qn and fill in the blanks)
Hypothalamus regulates body temperature based on the set point
What are the responses to control heat production and heat loss?
Heat production: muscle tone (tension and flexibility of muscle), shivering thermogenesis (the process of heat production by muscular contraction by skeletal muscles), and non-shivering thermogenesis (increase in metabolic heat production that is not associated with muscle activity)
Heat loss: sweating, skin vasoconstriction and vasodilation
Hypothalamic regulation of temperature: responses to cold exposure
Increase in heat production and decrease in heat output: shivering thermogenesis, skin vasoconstriction to minimize heat loss, non-shivering thermogenesis - increase in brown fat activity
Hypothalamic regulation of temperature: responses to heat exposure
Decrease in heat production and increase in heat output:
skin vasodilation to maximize heat loss, sweating (heat loss through evaporation of sweat on skin surface), decreased muscle tone (muscle tension decrease as the increased temperature leads to increased blood flow and increased O2 transported to the muscle cells, increasing muscle repair and relaxation)
State the dominant mechanism that is highly effective in controlling heat loss in environmental changes at:
1) below 20°C
2) between 20-30°C
3) above 30°C
1) Shivering
2) Skin vasomotor activity
3) Sweating
During a fever, describe what happens that leads to an increase in the hypothalamic set point and how that leads to a higher body temperature
During an infection, the neutrophils release cytokines (endogenous pyrogens) that leads to an increase in prostaglandins in the hypothalamus, resulting in an increase in the hypothalamic set point. This leads to the initiation of a “cold response” as the core body temperature is lower than the hypothalamic set point, resulting in an increase in heat production and decrease in heat loss, which thus leads to an increase in body core temperature, a symptom of fever
After a fever has passed, why does the body start sweating
After a fever, when prostaglandin concentration in the hypothalamus decreases, the hypothalamic set point also decreases and the body core temperature is now higher than the hypothalamic set point, which leads to the initiation responses to heat exposure, resulting in sweating to increase heat output
