K103 Exam Three- 2026 IUI

Types of Cell Communication: Electrical Signals

Used in nervous system

Fast (neurons)

Use neurotransmitters

Types of Cell Communication: Direct cell-to-cell contact

Cells must touch

Example: immune cells (T cells + B cells)

Types of Cell Communication: Chemical Signals

- Signals = ligands (hormones, neurotransmitters, etc.)

Travel in:

- Blood (endocrine)

- Interstitial fluid (paracrine)

- Bind to receptors → trigger response

Cell Response

- Ligand binds receptor → specific response

- Different cells → different responses to SAME signal

Hydrophilic Molecules

- act as extracellular messengers

- cannot cross the plasma membrane, binding instead to transmembrane receptors on the cell surface to trigger intracellular signaling cascades.

Hydrophobic Molecules

- generally lipid-soluble messengers that diffuse directly through the cell's plasma membrane to activate intracellular receptors

Intranuclear receptors

- Signal enters cell

- Goes to nucleus and binds receptor

- Turns genes ON/OFF

- Examples: Hydrophobic (no gas), steroid, or thyroid hormones

👉 Result: gene activation

*basically these are already in the nucleus and the ligand just binds directly in nucleus*

Cytosolic Receptor

- Binds ligands then move to nucleus

- they are in the cytoplasm

basically these are in the cytoplasm and the ligand binds and moves into nucleus

Agonist

Activates receptor

Hormone binds and stimulates a receptor

Combined effects:

Additive → effects add together

Synergistic → effect is bigger than sum

Antagonist

Blocks receptor

Hormone binding fails to initiate a response

Combined effects:

Additive → effects add together

Synergistic → effect is bigger than sum

4 steps of Cell Signaling: 1. Signal (Ligand)

A cell releases a signal:

Electrical → nerve impulses

Chemical → hormones, neurotransmitters

Direct contact → cells touching

4 steps of Cell Signaling: 2. Reception

Target cell has a receptor (like a lock)

Signal = key

Only correct cells respond

4 steps of Cell Signaling: 3. Transduction

Inside the cell → chain reaction

Uses:

enzymes

second messengers

ion channels

👉 This step amplifies the signal

4 steps of Cell Signaling: 4. Response

Cell does something:

change gene expression

open channels

release molecules

Reception and Response Strength are controlled at the CELL LEVEL by Up-regulation and Down-regulation

Up-regulation

More receptors → stronger response

Down-regulation

Fewer receptors → weaker response

Reception and Response Strength are controlled at the RECEPTOR LEVEL by affinity and specificity

Affinity: How easily, tightly a hormone binds

Specificity: similarity in hormone structure and receptor binding site

Reception and Response Strength are controlled at the EXTRACELLULAR LEVEL by Concentration

- Concentration of signals, how much of signal is present (synthesis, amount bound, breakdown)

Reception and Response Strength are controlled at the INTRACELLULAR LEVEL by

- The response will be determined by the intra cellular molecules activated

- Could cause altered membrane permeability, altered metabolism, and altered gene activity.

Signal Amplification

One signal → MANY effects

Example: 1 hormone → activates many molecules → big response

Types of Cell Surface Receptors: Ligand-gated Channels

Signal binds → channel opens

Ions move in/out

👉 Example: acetylcholine → Na⁺ enters → nerve signal

Types of Cell Surface Receptors: G Protein- Coupled Receptors

Signal binds → activates G protein

G protein:

opens channels OR

activates enzymes

Key enzymes:

Adenylyl cyclase

Phospholipase C

Types of Cell Surface Receptors: Enzyme- linked receptors

Directly activate enzymes

Types:

Tyrosine kinase

Guanylyl cyclase

👉 Example: insulin receptor

Overview of endocrine regulation

Hormone production:

Comes from:

Standalone glands (like thyroid)

OR specialized cells in other tissues

👉 So hormones don’t only come from “organs,” sometimes just specific cells.

Endocrine glands

Ductless → They don’t use tubes (ducts), they release directly into fluid

Release into:

Interstitial fluid (fluid around cells)

Then often into blood

Specialized function:

Make and secrete hormones (signaling molecules)

👉 Key idea: Endocrine = hormones released into blood to travel around body

Primary endocrine organs

Main function:

Hormone production AND secretion

Examples:

Hypothalamus

Pituitary gland

👉 These are the main control centers of the endocrine system

Secondary endocrine organs

Main function:

NOT mainly for hormone production/secretion

👉 They have other jobs, but can still release hormones

Examples:

Heart

Skin

Stomach

Endocrine and Nervous Systems Interact

The nervous system is:

Response:

Rapid

Short-lasting

👉 Compared to hormones (which are slower but longer-lasting)

Signals:

Uses:

Electrical signals (nerve impulses)

Chemical signals (neurotransmitters)

The endocrine system is:

🔸 Response

Slow, but longer lasting

👉 Opposite of nervous system (fast + short)

🔸 Effectors

Affects many cells and systems

👉 Hormones travel in blood → can impact the whole body

🔸 Systems connection

Connected by hypothalamus and pituitary

👉 These act as the link between nervous + endocrine systems

4 main chemical groups: 1. Fatty Acid Derivatives.

Examples:

Prostaglandins

Juvenile hormones (intestines)

👉 Made from lipids

4 main chemical groups: 2. Steroid Hormones.

Made from cholesterol

Examples:

Cortisol

Testosterone

Estrogen

Progesterone

👉 Lipid-soluble → can cross membranes

4 main chemical groups: 3. Amino Acid Derivatives

Example:

Thyroid hormones (T3 and T4)

Made from tyrosine + iodide

👉 Important exception: behave more like lipids

4 main chemical groups: 4. Peptide & protein hormones

Examples:

Insulin (protein hormone)

ADH (neuropeptide)

👉 Water-soluble → bind surface receptors

Neuroendocrine Signaling (Neurohormones)

Production

Made by nerve cells

🔸 Release

Released from axon terminal

🔸 Transport

Travel through:

Blood

OR interstitial fluid

👉 So neurons can act like endocrine cells

Local Signaling

What it is:

Signal diffuses through interstitial fluid

Acts on nearby cells

👉 Not traveling through whole body like hormones

Local Signaling type 1: Autocrine Signaling

Signal acts on same cell that produced it

Example:

Estrogen stimulates more estrogen release from same cell (ovary)

Local Signaling type 2: Paracrine Signaling

Signal acts on nearby cells

Examples:

Growth factors → cell division & development

Histamine → blood vessel dilation + ↑ permeability

Nitric oxide (NO) → relaxes smooth muscle in vessels

Prostaglandins - Cause smooth muscle contraction, Fever, Labor (childbirth)

Hormones and Insects Development

This is explaining how insects grow and change form (metamorphosis) using hormones.

👉 Basically: hormones control when an insect stays a larva vs becomes an adult

The 3 Main Hormones

1. Brain Hormone (BH)

Comes from the brain (neuroendocrine cells)

Stimulates prothoracic gland → produces molting hormone

Its job: 👉 Tells another gland to release molting hormone

2. Molting Hormone (Ecdysone)

Causes: 👉 Growth + molting (shedding outer layer)

👉 Every time this hormone is released → insect gets bigger

3. Juvenile Hormone (JH) ⭐ (MOST IMPORTANT)

What it does:

Keeps the insect immature

Suppresses metamorphosis at each larval molt

Insect:

Gets bigger

But stays immature

👉 Even after molting, it stays a larva

Changes in hormone level

JH decreases with each molt

Eventually:

Insect pupates

If JH is absent:

Insect becomes adult

👉 Key idea:

High JH = stay immature

Low/No JH = become adult

Neurohormones and Metamorphosis in Vertebrates

Concept:

Hormones can be affected by environment (like sunlight)

Example:

Less sunlight → changes in hormone levels → mood changes

Hormone Defined

🔸 Meaning:

From Greek → “excite” or “arouse”

🔸 Components:

Produced by:

Glands

Cells in tissues

Specialized nerves

🔸 Product:

Hormones

Chemical signals / messengers

🔸 Tropic and releasing hormones

Function:

Target other endocrine glands

👉 Example idea:

One hormone controls another gland’s hormone release

Secretion Abnormalities- Hyposecretion

Abnormally reduced hormone output

Secretion Abnormalities Hypersecretion

Abnormally increased hormone output

Other secretion abnormality

Sometimes:

Hormone is produced normally

BUT receptors don’t respond

👉 Problem can be signal OR receptor

Hypothalamus

🔸 Location:

Brain

🔸 Function:

Links nervous system + endocrine system

Controls:

Automatic (physiological) processes

Most endocrine activity

Directly or indirectly

👉 It’s the main control center

Pituitary Gland (Master Gland)

🔸 Location:

Connected to hypothalamus

🔸 Function:

Controls secretion of:

Other endocrine glands and tissues

👉 That’s why it’s called “master gland”

🔸 Structure:

Has 2 lobes:

Anterior

Posterior

hypothalamus and Posterior Pituitary Gland

🔸 Posterior Pituitary

🔹 Structure:

Axons from hypothalamus neurons extend into pituitary

👉 Meaning:

Hormones are made in hypothalamus, stored/released here

🔹 Hormones released:

Neurohormones (peptide hormones)

From hypothalamus:

🔸 Antidiuretic hormone (ADH)

Function:

Kidney water conservation

🔸 Oxytocin

Functions:

Uterine contractions

Social behaviors

Bonding (mother-infant, animals/humans)

Facial recognition & trust

hypothalamus and anterior Pituitary Gland (important ending)

Anterior Pituitary

🔹 Portal system structure (connection with hypothalamus)

Contains:

Capillary bed → vein → capillary bed

🔹 How it works:

Hormones enter capillaries in hypothalamus

Travel via blood to anterior pituitary

Then:

Diffuse out and act on target cells

🔸 Neurohormones affect anterior pituitary

Hypothalamus releases:

Releasing hormones

Inhibiting hormones

👉 These control what the anterior pituitary releases

🔸 AP (anterior pituitary) products

Produces its own hormones in response

Abnormal Secretion of growth hormone- Pituitary Dwarfism

Extreme deficiency of growth hormone during childhood

Abnormal Secretion of growth hormone- Gigantism

Excess growth hormone during childhood

👉 Leads to very tall height

Abnormal Secretion of growth hormone- Acromegaly

Hypersecretion during adulthood

Effects:

Connective tissue thickens

Bones increase in diameter (not length)

Hands

Feet

Face

Thyroid Gland

🔹 Thyroid Gland

🔸 Location:

Front of trachea, below larynx

🔸 Thyroid hormones

T3 and T4

Made from: Tyrosine + iodine

🔸 Functions:

Metabolic rate (BIG one)

Regulates proteins for: Cell differentiation

Ca²⁺ metabolism (later)

Calcitonin (helps with calcium regulation)

Heat Production

🔸 Cold temperature:

Hypothalamus increases:

TSH-releasing hormone

Leads to:

↑ Thyroid activity

↑ Heat production

👉 Thyroid helps regulate body temperature

Hypothyroidism (LOW thyroid)

🔸 Infancy & childhood:

Low metabolic rate

Can cause:

Cretinism

Delayed mental + physical development

🔸 Adulthood:

Myxedema

Slowed physical + mental activity

Hyperthyroidism

🔸 Most common form:

Graves disease

Autoimmune

🔸 Effects:

High metabolism

Weight loss

Irritability

Enlarged Thyroid

🔸 Goiter

Can result from:

Hyposecretion OR hypersecretion

👉 Not just one cause

Parathyroid Glands

🔸 Location:

Surround thyroid gland

🔸 Secretion:

Parathyroid hormone (PTH)

🔸 Function:

Works opposite (antagonistically) to calcitonin (from thyroid)

Regulates Ca²⁺ levels

Regulation of Calcium Homeostasis

🔸 Key hormones:

Calcitonin + PTH regulate calcium

🔸 Negative feedback cycle:

Once Ca²⁺ levels return to normal → hormone release stops

🔸 Effects:

Calcitonin → lowers blood Ca²⁺

PTH → increases blood Ca²⁺

Regulation of Glucose Metabolism- Pancreas

🔹 Function:

Regulates:

Blood glucose (primary)

Also fat & protein metabolism

🔹 Location:

Curve of small intestine

Near stomach, below liver

🔹 Function (mixed gland):

Endocrine → hormones (insulin, glucagon)

Exocrine → digestive enzymes

Endocrine function (Islets of Langerhans) - Alpha Cells

Produce glucagon

Function:

Raises blood sugar

Endocrine function (Islets of Langerhans) - Beta Cells

Produce insulin

Function:

Lowers blood sugar

Hormone Function: Insulin Stimulates

🔸 Insulin stimulates:

Glucose uptake from blood

Inhibits glucose release from liver

🔸 Result:

Blood glucose decreases

Hormone Function: Glucagon Stimulates: GLYCOGENOLYSIS

🔸 Glucagon stimulates:

🔹 Glycogenolysis

Liver:

Converts glycogen → glucose

🔸 Result:

Blood glucose increases

Hormone Function: Glucagon Stimulates: GLYCONEOGENESIS

Glucagon Stimulates:

🔹 Gluconeogenesis

Makes glucose from:

Non-carbohydrates

🔸 Result:

Blood glucose increases

Diabetes Mellitus

🔸 Description:

Group of disorders with:

High blood glucose levels

Most common endocrine disorder

Can lead to blindness and possibly death

Diabetes Mellitus Type 1

🔸 Type 1 (insulin dependent)

Decrease in beta cells

Requires:

Insulin injections

Cause:

Autoimmune disorder

Diabetes Mellitus Type 2

🔸 Type 2 (non-insulin dependent) (most common)

Often begins as type 1-like symptoms

Problem:

Lack of functional receptors on target cells

Managed by:

Exercise + diet

🔹 Metabolic Disturbances in Diabetes Mellitus

🔸 Decreased use of glucose

Cells:

Can’t take in glucose

Result:

Glucose appears in urine

🔸 Dehydration

Water follows glucose into urine 👉 Leads to excess urination + dehydration

🔸 Increased fat mobilization

Body uses fat for energy

Leads to:

Ketone bodies buildup

🔸 Electrolyte imbalance

Ketones cause loss of:

Na, K, and other ions in urine

🔸 Increased protein use

Body breaks down protein for energy

Result:

Weight loss, thin/emaciated

Hypoglycemia

🔸 Defined:

Low blood glucose

Can occur in:

People who later develop diabetes

🔸 Development:

Delayed response to glucose intake

Followed by:

Excess insulin release (hypersecretion)

🔸 Effects:

Blood glucose drops → person becomes:

Drowsy Uncoordinated Or unconscious

Serious Hypoglycemia (Insulin Shock)

Can happen if:

Diabetic receives too much insulin

Adrenal Glands - Adrenal Cortex

🔸 Location:

Outer tissue region

🔸 Hormones:

🔹 Androgens

Function:

Precursors to sex hormones:

Testosterone

Estradiol

🔹 Aldosterone

Acts on:

Kidneys

🔸 Function:

Regulates:

Na⁺ (sodium)

K⁺ (potassium)

🔸 Result:

Maintains:

Blood volume

Blood pressure

🔹 Cortisol

Function:

Stimulates glucose production in liver

👉 Especially during stress

Adrenal Glands- Adrenal Medulla

🔸 Location:

Inner tissue region

🔸 Hormones:

Epinephrine (adrenaline)

Norepinephrine

🔸 Effects (when hormones increase):

↑ Metabolic rate

↑ Blood flow to:

Brain

Muscles

Heart

↑ Conversion of:

Glycogen → glucose

🔹 Control

🔸 Controlled by:

Sympathetic nervous system (hypothalamus)

🔸 During stress:

Hypothalamus:

Activates sympathetic neurons

This triggers:

Release of adrenal medulla hormones

👉 This is the fight-or-flight response

Immune System Main Category 1- Innate Immunity

🔸 Features:

Immediate response

General protection

Same response for all pathogens

👉 No specificity, no memory

Immune System Main Category 1- Adaptive Immunity

🔸 Features:

Highly specific response

Targets specific pathogens

Has immunological memory

👉 Stronger response the second time

Invertebrate Innate Immune Response

🔸 Exoskeleton

Function:

Blocks pathogen entry

👉 Physical barrier

🔸 Mucus

Function:

Sticky → traps and blocks pathogens

👉 Prevents entry into body

Pattern Recognition Receptors (PRRs)

🔸 Function:

Recognize foreign molecules on microbes (like bacteria)

🔸 What they detect:

PAMPs (Pathogen-Associated Molecular Patterns)

Microbial proteins/molecules unique to pathogens

🔸 Process:

PRRs on phagocytes recognize PAMPs

→ Phagocytosis activated (engulfing pathogens)

🔸 Other responses:

Inflammation:

Recruits white blood cells (WBCs / lymphocytes)

Natural killer cells:

Destroy tumor cells + virus-infected cells

Antimicrobial proteins:

Help kill/inactivate pathogens

Immune Response Communality + requirements

🔸 Commonality in all immune responses:

Defends against:

Non-self molecules and organisms

🔸 Requirements:

Must:

Distinguish self vs non-self

Recognize:

Foreign cells

Harmful macromolecules

Detect unique proteins on cell surfaces

Communication with Immune Cells

🔸 Direct (cell-to-cell contact)

Uses:

Surface markers (MHC)

🔸 Indirect (soluble signals)

Cells release:

Signaling molecules to activate other cells

Vertebrate Immunity

🔸 Innate (nonspecific) immunity

Same response regardless of pathogen

🔹 First line of defense

Surface barriers (skin, etc.) 👉 First contact with body

🔹 Second line of defense

Immune cells:

Neutrophils

Eosinophils

Basophils

NK cells

Monocytes:

Leave blood → become:

Macrophages

Dendritic cells

🔸 Third line of defense (Adaptive immunity)

Activated when:

Innate immunity fails

🔹 Cells involved:

T cells

B cells (lymphocytes)

🔸 Function:

Response is:

Specific to a pathogen

Overview of Human Immune Responses- Innate Immune Response

🔹 Innate Immune Response (Rapid)

Happens immediately

🔸 Includes:

Barriers (skin, epithelial layers)

Pattern recognition receptors (PRRs)

Cytokines + complement proteins

NK (natural killer) cells

Dendritic cells

Phagocytes (macrophages)

🔸 Key processes:

Inflammation

Phagocytosis (engulfing pathogens)

Overview of Human Immune Responses- Adaptive Immune Response

🔹 Adaptive Immune Response (Slower)

Takes: Hours to days

🔸 Includes:

Cell-mediated immunity (T cells)

Antibody-mediated immunity (B cells)

Innate (nonspecific) immunity in vertebrates- examples

🔸 Physical Barriers

🔹 Skin (epithelium):

Unbroken body surface

Protects from environment

🔸 Functions:

Bacteria must:

Compete with normal skin microbes

Skin conditions:

Often too dry for growth

Acts as:

Protective secretion barrier

🔹 Internal linings (epithelium):

Found in:

Digestive

Respiratory

Urinary systems

🔸 Mucus:

Function:

Traps and removes pathogens

Pathogens are removed by Expelled, Swallowed, Removed by actions like blowing nose

Other Epithelial Secretions

🔸 Mucus (again emphasized)

Continues to trap pathogens

🔸 Body fluids:

Examples:

Tears

Urine

Saliva

Sweat (perspiration)

🔸 Functions:

Flush surfaces

Create: Unfavorable environment for microbes

🔸 Stomach acid

Function: Kills pathogens, it has unfavorable environment, the body creates conditions are not ideal for microbes, exceptions: E. Coli, Salmonella, H. pylori.

Antimicrobial Peptides (Produced by Epithelium)

🔸 Defensins

Function:

Work against bacteria

Produced by:

Cells of:

Mucosal linings

Also found in insect hemolymph

Actions:

Perforate bacterial membranes

Inhibit cell wall synthesis

🔸 Mucins

Glycoproteins in mucus

Function:

Give mucus: Gel-like, sticky properties

Help: Trap bacteria

In lungs: Assist in mucociliary clearance

🔸 Lysozyme

Found in: Tears, Saliva

Function:

Enzyme that: Breaks down bacterial cell walls

Molecules of Immune System- cytokines

🔸 Cytokines

Proteins that:

Enhance immune response

🔸 Produced by:

Many cells, especially:

Helper T cells

Macrophages

🔸 Functions:

Regulate:

Immune response

Cell growth

Repair

Activation

🔸 Named by:

Function and origin

Examples of Cytokines- Tumor Necrosis Factor

🔸 Tumor Necrosis Factor (TNF)

Directed toward:

Cell survival and death

🔸 Functions:

Attracts phagocytes

Increases phagocytosis

Stimulates release of more cytokines (positive feedback)

Causes:

Inflammation

Fever (later)

Flu-like symptoms

Examples of Cytokines- Interleukins

🔸 Interleukins

Signaling between:

Leukocytes (WBCs)

🔸 Stimulate:

Neutrophil production

Activation of:

NK cells

T cells

Interferon production

Examples of Cytokines- Interferons

🔸 Interferons

Function:

Inhibit viral replication

🔸 Also:

Stimulate:

Macrophages

NK cells

👉 Help destroy virus-infected cells

Examples of Cytokines- Chemokines

🔸 Chemokines

Type of cytokine

🔸 Function:

Direct leukocyte movement (chemotaxis)

Interferon (IFN)

🔸 What happens:

Infected cell releases interferons (IFN-α, IFN-β)

🔸 Effects on nearby cells:

Normal cells:

Produce enzymes that block viral replication

👉 Helps prevent spread of virus

🔸 Immune cell activation:

NK cells (natural killer cells):

Kill infected cells → apoptosis

Use: Perforin Granzymes

🔸 Macrophages:

Phagocytize (engulf) infected cells

Complement System

🔸 Description:

~50 proteins (made mainly by liver)

Named:

C1, C2, etc.

🔸 Functions:

Cell lysis (bursting pathogens)

Inflammation

Enhances phagocytosis

Clears immune complexes

Neutralizes viruses

Inflammatory Response

🔸 What it is: Nonspecific response

Triggered by: Injury or infection

🔸 Begins with:

Release of: Proteins + chemical mediators

👉 These recruit/activate immune cells

🔸 Causes: Damaged or injured cells, Activated basophils and mast cells

🔸 Key mediators: Histamines, Prostaglandins

🔸 Effects:

Cause: Leukocyte chemotaxis (WBC movement to site)

Pathogens also: Attract defensive cells

Three Main Processes Involved (Inflammation)- 1. Vasodilation

🔸 1. Vasodilation

🔹 Involves:

Macrophages + mast cells

Act as first responders (within minutes)

🔸 Mast cells release:

Histamine

Cytokines

Other molecules

🔸 Effects:

Vasodilation (blood vessels widen)

Causes:

Warmth

Redness

Three Main Processes Involved (Inflammation)- 2. Increased Capillary Permeability

🔹 Mast cells release molecules that:

Make capillaries more leaky

🔸 Result:

Antibodies + fluid enter tissues

Causes:

Edema (swelling)

Three Main Processes Involved (Inflammation)- 3. Increased Phagocytosis

🔹 Monocytes:

Quickly move to area

Undergo diapedesis

(leave blood vessels → enter tissues)

🔹 Macrophages:

Activated quickly

Functions:

Help contain pathogens

Recruit other phagocytes

Release pyrogens → cause fever

🔸 Fever:

Helpful because:

Body temp rises → outside optimal range for bacteria

🔹 Neutrophils:

Attracted by chemicals (chemotaxis)

Also undergo:

Diapedesis

🔸 Functions:

Enter tissues from blood

Engulf pathogens

Then die

🔸 Additional:

More neutrophils are:

Released from bone marrow

Newly produced

Additional effects of the inflammatory response

🔸 Clotting proteins

Wall off infection site

Help:

Isolate microbes

🔸 Persistent pain

Due to:

Increased nerve activity in area

🔸 Leukocytosis (high WBC count)

Indicator of:

Infection

🔸 Cytokine effects:

Stimulate production of:

Neutrophils

Monocytes

🔸 Result:

Increased removal of:

Pathogens

Dead cells

Facilitates healing

👉 Inflammation isn’t just defense — it helps repair tissue

Cells of Innate Immune System- Phagocytic Leukocytes- 1. Neutrophils

🔹 Neutrophils

Most numerous granulocytes

Chemotactic (move toward infection signals)

🔸 Function:

Kill pathogens using:

Digestive enzymes

Hydrogen peroxide

Hypochlorous acid

Cells of Innate Immune System- Phagocytic Leukocytes- 2. Eosinophils

Chemotactic

🔸 Function:

Release digestive enzymes (especially for parasites like worms)

Phagocytize antigen-antibody complexes

Can act as:

Antigen-presenting cells

Cells of Innate Immune System- Phagocytic Leukocytes- 3. Macrophages

🔹 Macrophages

Function:

Also act as antigen-presenting cells

👉 Important link between innate + adaptive immunity

Cells of Innate Immune System- Phagocytic Leukocytes- 4. Dendritic Cells

🔹 Dendritic Cells (Phagocytic)

🔸 Origin:

Arise from monocytes

Located in:

Tissues exposed to environment

🔸 Activation:

Activated by:

PAMPs

🔸 Activity:

Produce interferons

Act as:

Antigen-presenting cells

Nonphagocytic Cells of Immune System- NK Cells

🔹 Natural Killer (NK) Cells

🔸 Function:

Defend against:

Abnormal body cells

🔸 What they destroy:

Tumor cells

Infected cells (viruses + bacteria)

🔸 Characteristics:

Nonspecific, but can work with adaptive immunity

Respond to:

Transplanted tissues

🔸 Mechanism:

Release:

Perforins

Granzymes

🔸 Effects:

Lyse (break open) cells

Activate:

Apoptosis (programmed cell death)

🔸 Also:

Release cytokines

Nonphagocytic Cells of Immune System- Basophils

🔸 Characteristics:

Rarest granulocytes in blood

🔸 Function:

Involved in:

Inflammation

Conditions like asthma

Nonphagocytic Cells of Immune System- Mast Cells

🔹 Mast Cells

🔸 Location:

Found in:

Connective tissues

🔸 Function:

Involved in:

Inflammation

Wound healing