Podcast
Questions and Answers
What is Anatomy?
What is Anatomy?
The study of structure and the relationships among structures.
Which type of anatomy deals with structures that can be seen with the naked eye?
Which type of anatomy deals with structures that can be seen with the naked eye?
In anatomical position, where are the palms of the hands directed?
In anatomical position, where are the palms of the hands directed?
Inferior means toward the upper part of a structure.
Inferior means toward the upper part of a structure.
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What does 'proximal' mean?
What does 'proximal' mean?
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Match the following body cavities with their contents:
Match the following body cavities with their contents:
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Which body system is responsible for the exchange of gases?
Which body system is responsible for the exchange of gases?
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The process of using energy to build up body structures is called _____
The process of using energy to build up body structures is called _____
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Homeostasis is the maintenance of constant conditions in the body’s internal environment.
Homeostasis is the maintenance of constant conditions in the body’s internal environment.
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What type of feedback system opposes change?
What type of feedback system opposes change?
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What are the two major body cavities?
What are the two major body cavities?
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The thoracic cavity is separated from the abdominal cavity by the diaphragm.
The thoracic cavity is separated from the abdominal cavity by the diaphragm.
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What is the primary function of serous membranes?
What is the primary function of serous membranes?
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A __________ is a mass of similar cells that performs a specific function.
A __________ is a mass of similar cells that performs a specific function.
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Match the following components with their definitions:
Match the following components with their definitions:
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What term describes the division of the body into right and left halves?
What term describes the division of the body into right and left halves?
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The term 'medial' refers to a position farther from the midline of the body.
The term 'medial' refers to a position farther from the midline of the body.
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What is the anatomical position?
What is the anatomical position?
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The ____ section divides the body into anterior and posterior parts.
The ____ section divides the body into anterior and posterior parts.
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Match the following directional terms with their definitions:
Match the following directional terms with their definitions:
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Which of the following terms describes a cut along the body that divides it into anterior and posterior portions?
Which of the following terms describes a cut along the body that divides it into anterior and posterior portions?
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Contralateral refers to structures on the same side of the body.
Contralateral refers to structures on the same side of the body.
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Define 'proximo-distal' relationship.
Define 'proximo-distal' relationship.
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Which organ system includes the skin, hair, and nails?
Which organ system includes the skin, hair, and nails?
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The respiratory system includes the stomach and intestines.
The respiratory system includes the stomach and intestines.
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Name the two processes that make up metabolism.
Name the two processes that make up metabolism.
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The systematic study of living organisms requires the ability to sense changes known as _____ .
The systematic study of living organisms requires the ability to sense changes known as _____ .
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Which of the following is NOT an organ of the circulatory system?
Which of the following is NOT an organ of the circulatory system?
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Match the following organ systems to their primary components.
Match the following organ systems to their primary components.
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Differentiate means to increase the number of cells.
Differentiate means to increase the number of cells.
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Which organ system is responsible for transporting lymph and filtering blood?
Which organ system is responsible for transporting lymph and filtering blood?
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What is the primary role of the kidneys in homeostasis?
What is the primary role of the kidneys in homeostasis?
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Positive feedback systems are the primary method by which most control systems in the body operate.
Positive feedback systems are the primary method by which most control systems in the body operate.
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What type of feedback mechanism reverses the initial condition when a variable departs from its normal limits?
What type of feedback mechanism reverses the initial condition when a variable departs from its normal limits?
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The _____ provide oxygen to the body, which is necessary for homeostasis.
The _____ provide oxygen to the body, which is necessary for homeostasis.
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Match the physiological components with their functions:
Match the physiological components with their functions:
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What are the four principal parts of a cell?
What are the four principal parts of a cell?
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What is the thickness range of the plasma membrane?
What is the thickness range of the plasma membrane?
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What is the main job of glycolipids in the plasma membrane?
What is the main job of glycolipids in the plasma membrane?
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Which of the following is NOT a function of the plasma membrane?
Which of the following is NOT a function of the plasma membrane?
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Small molecules like water can easily pass through the plasma membrane.
Small molecules like water can easily pass through the plasma membrane.
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What is the cytoplasm primarily composed of?
What is the cytoplasm primarily composed of?
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What is the function of organelles in the cell?
What is the function of organelles in the cell?
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The smallest structure within the cell, responsible for protein synthesis, is the ______.
The smallest structure within the cell, responsible for protein synthesis, is the ______.
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Mitochondria are responsible for producing ATP.
Mitochondria are responsible for producing ATP.
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What are lysosomes primarily used for?
What are lysosomes primarily used for?
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Which of the following is a component of the cytoskeleton?
Which of the following is a component of the cytoskeleton?
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What role does cholesterol play in the plasma membrane?
What role does cholesterol play in the plasma membrane?
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Match the following organelles with their functions:
Match the following organelles with their functions:
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What is the basic functional unit of the body?
What is the basic functional unit of the body?
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Which of the following are principal parts of a cell? (Select all that apply)
Which of the following are principal parts of a cell? (Select all that apply)
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The plasma membrane is responsible for selective permeability.
The plasma membrane is responsible for selective permeability.
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The hydrophilic head-group of a phospholipid is _____ in water.
The hydrophilic head-group of a phospholipid is _____ in water.
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What is the main function of ribosomes?
What is the main function of ribosomes?
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What are the two types of endoplasmic reticulum? (Select all that apply)
What are the two types of endoplasmic reticulum? (Select all that apply)
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Lysosomes are involved in energy production.
Lysosomes are involved in energy production.
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What is the function of mitochondria?
What is the function of mitochondria?
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Match the following cell organelles with their functions:
Match the following cell organelles with their functions:
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The cytoplasm is primarily composed of _____ and provides a medium for chemical reactions.
The cytoplasm is primarily composed of _____ and provides a medium for chemical reactions.
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What role do microtubules play in the cytoskeleton?
What role do microtubules play in the cytoskeleton?
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Study Notes
What is Anatomy?
- Study of the structure and relationships among structures.
- Gross Anatomy: Structures visible to the naked eye.
- Surface Anatomy: Deals with the form and markings of the body's surface.
- Histology: Microscopic study of tissue structure.
Anatomical Position
- Subject stands erect, facing the observer.
- Upper extremities are placed at the sides.
- Palms of the hands are turned forward.
Directional Terms
- Superior: Toward the head or upper part of a structure.
- Inferior: Away from the head or toward the lower part of a structure.
- Anterior: Nearer to or at the front of the body.
- Posterior: Nearer to or at the back of the body.
- Medial: Nearer to the midline of the body or a structure.
- Lateral: Farther from the midline of the body or a structure.
- Intermediate: Between two structures.
- Ipsilateral: On the same side of the body.
- Contralateral: On the opposite side of the body.
- Proximal: Nearer to the attachment of an extremity to the trunk or a structure.
- Distal: Farther from the attachment of an extremity to the trunk or a structure.
- Superficial: Toward or on the surface of the body.
- Deep: Away from the surface of the body.
- Parietal: Pertaining to or forming the outer wall of a body cavity.
- Visceral: Pertaining to the covering of an organ.
Body Planes and Sections
- Sagittal Section: Longitudinal cut dividing the body into right and left halves. A midsagittal or median section divides into equal halves.
- Frontal Section: Longitudinal cut dividing the body into anterior and posterior parts. Also called a coronal section.
- Transverse Section: Horizontal cut dividing the body into superior and inferior parts. Also called a cross section.
Body Cavities and Membranes
-
Dorsal Body Cavity:
- Cranial Cavity: Contains the brain, enclosed by the cranium.
- Vertebral Canal: Contains the spinal cord, enclosed by the vertebral column.
- Lined by meninges.
-
Ventral Body Cavity:
- Thoracic Cavity: Contains heart and lungs.
- Abdominopelvic Cavity: Contains digestive, urinary, and reproductive organs.
- Separated by the diaphragm.
- Lined by serous membranes: pleura, peritoneum
What is Physiology?
- The science of functional mechanisms of living organisms.
- Examples: Processes maintaining the identity of a living body during its exchange with its surroundings, receiving information from the surroundings, and reacting to influence the environment.
The Hierarchy of Complexity
- System Level: Group of organs working together.
- Organ Level: Structure composed of two or more tissue types.
- Tissue Level: Mass of similar cells and cell products.
- Cellular Level: The basic structural and functional unit of living organisms.
- Chemical Level: The simplest level of organization.
Tissues & Organs
- A tissue is a mass of similar cells and cell products that forms a discrete region of an organ and performs a specific function.
- An organ is a structure composed of two or more tissue types that work together to carry out a particular function.
Organ Systems
- Integumentary System: Skin, hair, nails, cutaneous glands.
- Skeletal System: Bones, cartilage, ligaments.
- Muscular System: Skeletal muscles.
- Nervous System: Brain, spinal cord, nerves, ganglia.
- Endocrine System: Pituitary gland, thyroid gland, adrenal glands, pancreas, ovaries, testes.
- Reproductive System: Male: Testes, penis, associated ducts and glands. Female: Ovaries, uterus, vagina, associated ducts and glands.
- Circulatory System: Heart, blood vessels.
- Lymphatic System: Lymph nodes, lymphatic vessels, thymus, spleen, tonsils.
- Respiratory System: Nose, pharynx, larynx, trachea, bronchi, lungs.
- Urinary System: Kidneys, ureters, bladder, urethra.
- Digestive System: Teeth, tongue, salivary glands, esophagus, stomach, small and large intestine, liver, gallbladder, pancreas.
Life Processes
-
Metabolism: Sum of chemical reactions in the body.
- Anabolism: Building up body structures.
- Catabolism: Breaking down substances to provide energy.
- Excitability: Ability to sense and respond to changes.
- Conductivity: Ability to carry stimulus effects from one part of a cell to another.
- Contractility: Capacity of cells to shorten and change form.
- Growth: Increase in cell size and numbers.
- Differentiation: Unspecialized cells changing into specialized cells with specific structure and function.
- Reproduction: Formation of new cells or reproduction of a new individual.
Homeostasis
- Maintenance of constant conditions in the body's internal environment.
- Internal environment contains oxygen, glucose, ions, fatty substances, and other components.
- Cells can only live, grow, and function if these substances are maintained at proper concentrations.
- All organs participate in homeostasis.
Control Systems
-
Feedback systems regulate the internal environment.
-
Negative Feedback: Reverses the direction of the initial condition.
- Example: Nervous control of blood pressure. Pressure-sensitive cells in arteries detect increased pressure and send information to the brain. The brain signals the heart to beat slower and arterioles to dilate, decreasing blood pressure.
-
Positive Feedback: Amplifies the initial condition, often leading to instability and death.
- Example: If the brain signaled the heart to beat faster, blood pressure would continue to rise.
-
Most control systems in the body operate by negative feedback.
What is Anatomy?
- The study of structure and the relationships among structures
- Gross Anatomy: Structure visible to the naked eye
- Surface anatomy: Focuses on the form and markings of the body's surface
- Histology: Microscopic study of tissue structure
The Anatomical Position
- Subject stands erect, facing the observer
- Upper limbs are at the sides
- Palms of the hands are turned forward
Directional Terms
- Superior: Towards the head or upper part of a structure
- Inferior: Away from the head or towards the lower part of a structure
- Anterior: Nearer to the front of the body
- Posterior: Nearer to the back of the body
- Medial: Nearer to the midline of the body or a structure
- Lateral: Farther from the midline of the body or a structure
- Intermediate: Between two structures
- Ipsilateral: On the same side of the body
- Contralateral: On the opposite side of the body
- Proximal: Nearer to the attachment of an extremity to the trunk or a structure
- Distal: Farther from the attachment of an extremity to the trunk or a structure
- Superficial: Towards or on the surface of the body
- Deep: Away from the surface of the body
- Parietal: Pertaining to or forming the outer wall of a body cavity
- Visceral: Pertaining to the covering of an organ
Body Planes and Sections
- Sagittal Section: A cut along the body's longitudinal plane, dividing it into right and left halves. A midsagittal or median section creates equal halves.
- Frontal Section: A cut along the body's longitudinal plane, dividing it into anterior and posterior parts. Also known as a coronal section.
- Transverse Section: A cut made along the body's horizontal plane, dividing it into superior and inferior parts. Also known as a cross section.
Body Cavities & Membranes
- Two major body cavities: Dorsal and Ventral Body Cavities
- Organs within these cavities are called viscera
- Serous membranes line the cavities and cover the viscera, holding them in place.
Dorsal Body Cavity
- Contains:
- Cranial Cavity: Encloses the brain
- Vertebral Canal: Encloses the spinal cord
- Lined by three membranes called the meninges
Ventral Body Cavity
- Contains:
- Thoracic Cavity
- Abdominopelvic Cavity
- Separated by the diaphragm
- Lined by serous membranes:
- Pleura
- Peritoneum
What is Physiology?
- The science of functional mechanisms of living organisms
- Examples:
- Processes maintaining the identity of a living body during its exchange with its surroundings
- How information is received from the surroundings and how an organism reacts to influence its environment
The Hierarchy of Complexity
- System Level
- Organ Level
- Tissue Level
- Cellular Level
- Chemical Level
Tissues & Organs
- A tissue is a mass of similar cells and cell products forming a distinct region of an organ.
- An organ is composed of two or more tissue types working together to perform a specific function.
Organ Systems
- The body has 11 organ systems:
- Integumentary System
- Skeletal System
- Muscular System
- Nervous System
- Endocrine System
- Reproductive System
- Circulatory System
- Lymphatic System
- Respiratory System
- Urinary System
- Digestive System
Integumentary System
- Includes:
- Skin
- Hair
- Nails
- Cutaneous Glands
Skeletal System
- Includes:
- Bones
- Cartilage
- Ligaments
Muscular System
- Includes:
- Skeletal Muscles
Nervous System
- Includes:
- Brain
- Spinal Cord
- Nerves
- Ganglia
Endocrine System
- Secretes hormones that regulate various bodily functions -- detailed information not provided
Reproductive System
- Includes organs for reproduction -- detailed information not provided
Circulatory System
- Includes:
- Heart
- Blood Vessels
Lymphatic System
- Includes:
- Lymph Nodes
- Lymphatic Vessels
- Thymus
- Spleen
- Tonsils
Respiratory System
- Includes:
- Nose
- Pharynx
- Larynx
- Trachea
- Bronchi
- Lungs
Urinary System
- Includes organs for filtering waste from the blood -- detailed information not provided
Digestive System
- Includes:
- Teeth
- Tongue
- Salivary Glands
- Oesophagus
- Stomach
- Small and Large Intestine
- Liver
- Gallbladder
- Pancreas
Life Processes (1)
-
Metabolism: Sum of all chemical reactions in the body
- Anabolism: Building up body structures using energy
- Catabolism: Breaking down substances to provide energy for life
- Excitability: Ability to sense changes within and around an organism, and respond in a beneficial way
- Conductivity: Ability to carry the effect of a stimulus from one part of a cell to another, highly developed in nerve cells and to a lesser extent in muscle cells.
Life Processes (2)
- Contractility: Ability of cells to shorten and change form, particularly prominent in muscle cells
- Growth: Increase in cell size and number
- Differentiation: Unspecialized cells changing to specialized cells with specific structure and function
- Reproduction: Formation of new cells or reproduction of a new individual, transmitting life across generations.
Homeostasis
- Maintaining constant conditions in the body's internal environment
- Cells require specific concentrations of oxygen, glucose, ions, fatty substances, and other constituents to live, grow, and function.
- All organs contribute to homeostasis:
- Lungs provide oxygen
- Kidneys maintain constant ion concentrations
- Gastrointestinal tract provides nutrients
Control Systems
- Regulating devices that oppose change and restore balance to the internal environment
- Feedback systems: Information is continuously reported (fed back) to a control center, leading to positive or negative responses.
Negative Feedback
- When a variable deviates from its normal limits, the control center issues impulses to regulate it and bring it back to its usual level.
- Reverses the direction of the initial condition.
- Example: Nervous Control of Blood Pressure
- Pressure-sensitive cells in the walls of large arteries detect increased blood pressure.
- Information is sent to the control center in the brain.
- The brain sends impulses to:
- Slow the heart rate
- Dilate arterioles
- Blood pressure decreases until it reaches its normal level.
Positive Feedback
- If the control center signals the heart to beat faster, blood pressure would continue to rise.
- Leads to instability and death.
- Nearly all control systems in the body operate through negative feedback.
The Cell
- The basic, living, structural, and functional unit of the body
- Composed of four main parts:
- Plasma membrane
- Cytoplasm
- Organelles
- Inclusions
The Plasma Membrane
- Outer limiting membrane separating the cell's internal parts from the extracellular fluid and the external environment
- 6.5 - 10 nm in thickness
- Composed of:
- Phospholipids
- Proteins
- Cholesterol
- Glycolipids
- Water
- Carbohydrates
- Ions
Phospholipids
- Arranged in two parallel rows forming a lipid bilayer
- Each phospholipid consists of:
- A hydrophilic head-group
- Two long hydrophobic hydrocarbon chains
- In water, lipids spontaneously form a two-layered film with the hydrophilic heads pointing outwards and hydrophobic tails packed together
Glycolipids
- Located on the outer surface of the plasma membrane
- Contain an oligosaccharide in the hydrophilic head projecting outwards
Proteins
- Main functional elements embedded in the lipid matrix
- Some proteins extend through the whole membrane
- Others are only anchored to the outer or inner layer
- Some provide channels for water and ions to diffuse in and out of the cell
- Hydrophobic parts are within the lipid membrane, with polar or hydrophilic groups on their outer surfaces
- Many proteins on the outside are glycoproteins
- Glycoproteins provide receptor sites for recognition of cells, hormones, nutrients, and other chemicals
Cholesterol
- Almost equal in number to phospholipids
- Interspersed among phospholipids
- Stabilise the cell membrane
Functions of the Plasma Membrane
- A flexible boundary that encloses cellular contents and separates them from the external environment.
- Facilitates contact with other body cells or foreign cells or substances.
- Provides receptors for chemicals like hormones, neurotransmitters, enzymes, nutrients, and antibodies.
- Mediates the entrance and exit of certain substances and restricts the passage of others
- This is called selective permeability.
- The permeability of the plasma membrane is determined by several factors:
- Size of the molecules
- Solubility in lipids
- Charge of the ions
- Presence of carrier molecules
Cytoplasm
- Substance inside the cell's plasma membrane and external to the nucleus
- Matrix or ground substance of the cell
- Thick, semitransparent, elastic fluid containing the cytoskeleton
- Made up of:
- Water - 75-90% of cytoplasm
- Proteins
- Carbohydrates
- Lipids
- Inorganic substances
Cytoplasm Functions
- Site of some chemical reactions, including:
- Synthesis of new substances
- Chemical packaging for transport to other parts of the cell.
- Facilitates the excretion of waste materials.
Organelles
- Specialized portions of the cell that assume roles in:
- Growth
- Maintenance
- Repair
- Control
Organelles Include:
- Nucleus
- Ribosomes
- Endoplasmic reticulum
- Golgi complex
- Mitochondria
- Lysosomes
- Centrosome and centrioles
Nucleus
- Usually round or oval
- Largest structure in the cell
- "Control center" of the cell
- Separated from the cytoplasm by a nuclear membrane, which contains several small pores
- Contains genetic material DNA and RNA that controls protein synthesis.
Ribosomes
- Tiny granules consisting of ribosomal RNA (rRNA)
- Found on the rough endoplasmic reticulum or scattered within the cytoplasm
- Sites of protein synthesis.
Endoplasmic Reticulum
- System of parallel membranes surrounding a network of channels
- Continuous with the nuclear membrane
- Two types:
- Granular (rough) ER - dotted with ribosomes
- Agranular (smooth) ER - without ribosomes
Endoplasmic Reticulum Functions
- Provides a surface area for chemical reactions
- Acts as a transport channel for various substances
- Serves as a storage site for synthesized molecules
- Plays a role in packaging molecules with the Golgi complex.
Golgi Complex
- Usually situated near the nucleus
- Made up of 4 to 8 flattened membranous sacs stacked upon one another
- Main functions:
- Process, sort, and deliver proteins to various parts of the cell
- Lipid packaging and secretion
Mitochondria
- Sausage-shaped structures scattered throughout the cytoplasm
- Each mitochondrion has two membranes:
- Outer membrane - smooth
- Inner membrane - folded upon itself forming cristae, providing a large surface area for chemical reactions to take place.
- Provide energy for the cell by producing ATP.
Lysosomes
- Small spherical structures dispersed throughout the cytoplasm.
- Contain powerful digestive enzymes.
- Function: Remove debris from within the cell.
Centrosome and Centrioles
- Centrosome is a dense area of the cytoplasm located near the nucleus
- It contains a pair of cylindrical structures called centrioles
- Centrioles play a part in spindle formation during cell division.
Cell Inclusions
- Melanin - pigment stored in cells of the skin, hair, and eyes
- Protects the body from harmful ultraviolet rays
- Glycogen - polysaccharide stored in the liver, skeletal muscle cells, and vaginal mucosa
- Broken down by the liver into glucose
- Lipids - stored in adipocytes
- Decomposed, producing energy
- Mucus - provides lubrication and protection
The Cytoskeleton
- Collection of protein filaments and cylinders
- Determines the shape of the cell
- Provides structural support
- Organizes cell contents
- Moves substances through the cell
Components of the Cytoskeleton
- Microfilaments:
- 6 nm thick
- Made of protein actin
- Keep phospholipids together
- Intermediate Filaments:
- 8-10 nm thick
- Stiffer
- Resist stresses
- Microtubules:
- 25 nm in diameter
- Cylinders made up of filaments.
The Cell
- The cell is the fundamental, living, structural, and functional unit of the body.
- A cell is composed of the following four key parts:
- Plasma membrane
- Cytoplasm
- Organelles
- Inclusions
The Plasma Membrane
- The plasma membrane is the outer limiting membrane that separates a cell's internal parts from the extracellular fluid and the external environment.
- It is a thin structure, measuring only 6.5 to 10 nanometers in thickness.
- The plasma membrane is made up of the following:
- Phospholipids
- Proteins
- Cholesterol
- Glycolipids
- Water
- Carbohydrates
- Ions
Phospholipids
- Phospholipids are arranged in two parallel rows forming a lipid bilayer.
- Each phospholipid consists of a hydrophilic head group and two long hydrophobic hydrocarbon chains.
- In water, these lipids spontaneously form a bilayer with hydrophilic heads pointing outwards towards the water, while the hydrophobic tails pack together inside the bilayer.
Glycolipids
- Glycolipids are located on the outer surface of the plasma membrane.
- They have an oligosaccharide in the hydrophilic head, extending like hair into the surroundings.
Proteins
- Proteins are the primary functional elements embedded within the lipid matrix of the plasma membrane.
- Some proteins extend across the entire membrane, while others anchor only to the outer or inner layers.
- Certain proteins create channels for water and ions to diffuse in and out of the cell.
- These proteins orient themselves with hydrophobic parts within the lipid membrane and polar/hydrophilic groups on their outer surfaces.
- Many proteins on the outer surface are glycoproteins, providing receptor sites for cell recognition, hormones, nutrients, and other chemicals.
Cholesterol
- Cholesterol molecules are present in numbers almost equal to phospholipids.
- They are dispersed among phospholipids within the plasma membrane.
- Cholesterol helps stabilize the cell membrane.
Functions of the Plasma Membrane
- Acts as a flexible barrier, encapsulating cellular contents and separating them from the external environment.
- Facilitates contact between body cells, as well as with foreign cells or substances.
- Provides receptor sites for chemicals such as hormones, neurotransmitters, enzymes, nutrients, and antibodies.
- Mediates the entry and exit of specific substances while restricting the passage of others, exhibiting selective permeability.
Factors Affecting Permeability of the Plasma Membrane
- Size of molecules: Small molecules such as water and amino acids can enter and exit the cell easily, while larger molecules, like proteins, cannot.
- Solubility in lipids: Lipid-soluble substances such as oxygen, carbon dioxide, and steroid hormones pass through the cell membrane more rapidly.
- Charge on ions: The charge on an ion influences its ease of entry and exit, with ions opposite in charge to the membrane being attracted and passing through more readily.
- Presence of carrier molecules: Certain integral proteins can attract and transport substances across the membrane independent of the previously mentioned factors.
Cytoplasm
- The cytoplasm is the substance found inside the cell's plasma membrane, excluding the nucleus.
- It serves as the matrix or ground substance of the cell.
- It is a thick, semi-transparent, elastic fluid containing the cytoskeleton.
- The cytoplasm is composed of the following:
- Water (75-90%)
- Proteins
- Carbohydrates
- Lipids
- Inorganic substances
Functions of the Cytoplasm
- The cytoplasm is the site where various chemical reactions take place, including:
- Synthesis of new substances.
- Packaging of chemicals for transport to other parts of the cell.
- It facilitates the excretion of waste materials.
Organelles
- Organelles are specialized parts of the cell that play roles in growth, maintenance, repair, and control.
- They include:
- Nucleus
- Ribosomes
- Endoplasmic reticulum
- Golgi complex
- Mitochondria
- Lysosomes
- Centrosome and centrioles
Nucleus
- Usually round or oval, it is the largest structure within the cell.
- It serves as the "control center" of the cell.
- It is separated from the cytoplasm by a nuclear membrane containing multiple small pores.
- The nucleus contains the genetic material DNA, as well as RNA, which plays a crucial role in protein synthesis.
Ribosomes
- These are tiny granules composed of a type of RNA called ribosomal RNA (rRNA).
- They can be found attached to the rough endoplasmic reticulum or scattered throughout the cytoplasm.
- Ribosomes are the sites where protein synthesis occurs.
Endoplasmic Reticulum
- The endoplasmic reticulum consists of a system of parallel membranes surrounding a network of channels.
- It is continuous with the nuclear membrane.
- There are two types of the endoplasmic reticulum:
- Granular (rough) ER: Dotted with ribosomes.
- Agranular (smooth) ER: Lacking ribosomes.
Functions of the Endoplasmic Reticulum
- Provides a surface area for chemical reactions.
- Acts as a transport channel for various substances to move between different parts of the cell.
- Serves as a storage site for synthesized molecules.
- Plays a role in packaging molecules along with the Golgi complex.
Golgi Complex
- Usually located near the nucleus.
- Made up of four to eight flattened membranous sacs stacked on top of each other.
Functions of the Golgi Complex
- To process, sort, and deliver proteins to various parts of the cell.
- Lipid packaging and secretion.
Mitochondria
- Sausage-shaped structures scattered throughout the cytoplasm.
- Each mitochondrion consists of two membranes:
- The outer membrane – smooth.
- The inner membrane – folded upon itself forming cristae, which provide a large surface area for chemical reactions.
Function of Mitochondria
- Provide energy for the cell by producing ATP.
- This process involves a series of reactions:
- Glycolysis
- Krebs' Cycle
Lysosomes
- Small spherical structures dispersed throughout the cytoplasm.
- They contain potent digestive enzymes.
- Their function is to remove cellular debris.
Centrosome & Centrioles
- The centrosome is a dense area of cytoplasm located near the nucleus.
- It contains a pair of cylindrical structures called centrioles.
- These play a role in spindle formation during cell division.
Cell Inclusions
- These are non-living substances found within the cytoplasm, including:
- Melanin: A pigment stored in skin, hair, and eye cells, protecting the body from harmful ultraviolet rays.
- Glycogen: A polysaccharide stored in the liver, skeletal muscle cells, and vaginal mucosa. It is broken down by the liver into glucose.
- Lipids: Stored in adipocytes and can be decomposed to produce energy.
- Mucus: Provides lubrication and protection.
The Cytoskeleton
- This is a network of protein filaments and cylinders within the cytoplasm.
Function of the Cytoskeleton
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Determines the shape of the cell.
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Provides structural support.
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Organizes cellular contents.
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Moves substances through the cell.
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Types of Structures Within the Cytoskeleton:
- Microfilaments: These are 6nm thick, made of the protein actin, and help hold phospholipids together.
- Intermediate Filaments: These are 8-10nm thick, stiffer, and aid in resisting stresses.
- Microtubules: These are 25nm in diameter, cylinder-shaped structures made up of filaments.
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Description
This quiz covers the foundational concepts of anatomy, including the study of body structures and their relationships. It explores various branches such as gross anatomy and histology, and introduces key directional terms used in anatomical descriptions. Test your knowledge on the anatomy fundamentals and directional terminology essential for understanding the human body.
