Anatomy & Physiology Lab Study Notes: Cells, Tissues, Blood, Endocrine, and Nervous System

Lab 1: Cells and Tissues

1. Cell Structures

Cells are the basic structural and functional units of life. Understanding their components is essential for studying physiology.

• Plasma Membrane

  • Structure: Phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

    • Hydrophilic regions: Polar heads of phospholipids.

    • Hydrophobic regions: Fatty acid tails.

    • Amphiphilic molecules: Phospholipids (both polar and nonpolar regions).

  • Function: Selective permeability—controls substance movement, provides structure, supports communication via receptors and transport proteins.

• Cytoplasm & Cytosol

  • Cytoplasm: All internal contents except the nucleus.

  • Cytosol: Fluid portion; contains enzymes, ions, nutrients; site of glycolysis and other metabolic reactions.

• Organelles Overview

  • Nucleus: Contains DNA, site of transcription (DNA → RNA).

  • Ribosomes: Protein synthesis; free ribosomes make cytoplasmic proteins, bound ribosomes make secreted/membrane proteins.

  • Rough ER: Protein synthesis and modification.

  • Smooth ER: Lipid synthesis, detoxification, calcium storage.

  • Golgi Apparatus: Modifies, sorts, and packages proteins into vesicles.

  • Vesicles: Membrane sacs for transport.

  • Mitochondria: Site of ATP production through aerobic respiration.

  • Lysosomes: Contain hydrolytic enzymes to digest worn-out organelles and waste.

2. Extracellular vs Intracellular Fluid

Body fluids are divided into compartments with distinct ionic compositions.

Ion	Inside Cell (ICF)	Outside Cell (ECF)
Na+	15 mM	145 mM
K+	150 mM	5 mM
Ca2+	0.0001 mM	2.5 mM

• Similar compartments: Interstitial fluid and plasma (both extracellular).

• Differences: ICF high in K+ and proteins; ECF high in Na+ and Cl-.

3. Four Tissue Types

Tissues are groups of cells with similar structure and function.

1. Connective: Structure, transport, defense; extracellular matrix of collagen, proteoglycans, glycosaminoglycans.

2. Epithelial: Lines surfaces, glands, vessels; has basal lamina. Endothelium lines blood vessels.

3. Muscle: Skeletal (voluntary), cardiac (involuntary, striated), smooth (involuntary).

4. Neuronal: Communication via electrical and chemical signals.

4. Osmosis & Tonicity

Osmosis is the movement of water across membranes; tonicity describes the effect of a solution on cell volume.

• Tonicity:

  • Hypotonic: Cell swells.

  • Isotonic: No change.

  • Hypertonic: Cell shrinks.

• Normal blood osmolarity: 275–295 mOsm/kg.

• Osmolarity formula: $\text{Osmolarity} = \Sigma (\text{molar concentration} \times \text{number of particles})$

5. pH & Nernst Equation

pH measures hydrogen ion concentration; the Nernst equation predicts membrane potential for a given ion.

• pH: $\text{pH} = -\log[\text{H}^+]$

• Lower pH = higher [H+]; a change of 1 pH = 10× difference in [H+].

• Nernst Equation: $E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{out}}}{[\text{ion}]_{\text{in}}} \right)$ Where:

  • R = gas constant

  • T = temperature

  • z = ion charge

  • F = Faraday's constant

  More positive potential if [outside] > [inside].

6. Cell Cycle & Mitosis

Cells divide through a regulated cycle to produce new cells for growth and repair.

• Interphase: G1 (growth), S (DNA replication), G2 (prep).

• Mitosis:

  1. Prophase: Chromosomes condense.

  2. Metaphase: Align on equator.

  3. Anaphase: Sister chromatids separate.

  4. Telophase: Nuclear membranes form.

7. Microscopy

Microscopes are essential tools for visualizing cells and tissues.

• Parts: Base, arm, stage, objectives, coarse/fine focus, condenser, diaphragm.

• Handling: Hold by arm and base.

• Focusing: Start low power → coarse → fine focus.

• Contrast: Adjust diaphragm—closing it increases contrast.

Lab 2: Red Blood Cells

1. Blood Structure & Formed Elements

Blood consists of plasma and formed elements, each with specific functions.

• Plasma (55%): Water, proteins (albumin, fibrinogen, globulins), ions, nutrients, hormones.

• Formed Elements (45%):

  • Erythrocytes (RBCs): Transport O2, CO2 via hemoglobin.

  • Leukocytes (WBCs): Immune defense.

  • Thrombocytes (Platelets): Blood clotting.

Relative Numbers: RBCs >> Platelets >> WBCs

Cell Type	Typical Count
RBCs	~5 × 106/μL (millions per μL)
WBCs	~7 × 103/μL (thousands per μL)
Platelets	~2.5 × 105/μL (hundreds of thousands per μL)

• Polycythemia: Too many RBCs.

2. Ion & Solute Concentrations in Blood

Blood plasma contains tightly regulated concentrations of ions and solutes.

Ion	Normal Plasma Concentration	Disorder
Na+	135–145 mM	Hyponatremia / Hypernatremia
K+	3.5–5.0 mM	Hypokalemia / Hyperkalemia
Ca2+	2.2–2.6 mM	Hypocalcemia / Hypercalcemia
Glucose	70–110 mg/dL (3.9–6.1 mM)	Hypoglycemia / Hyperglycemia

• Natremina: Sodium levels

• Kalemia: Potassium levels

• Calcemia: Calcium levels

• Glycemia: Glucose levels

• Capnia: CO2 levels

3. Diagnostic Blood Tests

Blood tests help diagnose and monitor health conditions.

• CBC (Complete Blood Count): RBC, WBC, hemoglobin, hematocrit, platelets.

• CMP (Comprehensive Metabolic Panel): Electrolytes, glucose, liver/kidney enzymes, proteins.

• Normal ranges:

  • Hematocrit: ~40–50% (men), 36–45% (women)

  • Hemoglobin: 13–17 g/dL (men), 12–15 g/dL (women)

4. Hematocrit

Hematocrit is the percentage of RBCs in total blood volume.

• High: Polycythemia; Low: Anemia.

• Plasma % = 100 – Hematocrit %

5. RBC Count

RBCs are counted using a hemocytometer; calculation uses dilution factor and chamber volume.

• Formula Example: $\text{RBC count} = \frac{(\text{# cells counted}) \times (\text{dilution factor}) \times (1)}{\text{volume counted}}$

6. Hemoglobin Counts

Hemoglobin is measured by color comparison, spectrophotometer, or chemical test.

• Healthy Ranges: 12–17 g/dL.

7. Wintrobe Indices

Indices describe RBC size and hemoglobin content.

Index	Formula	Description
MCV (Mean Corpuscular Volume)	$\text{MCV} = \frac{\text{Hematocrit} \times 10}{\text{RBC count}}$	Size of RBCs
MCH (Mean Corpuscular Hemoglobin)	$\text{MCH} = \frac{\text{Hemoglobin} \times 10}{\text{RBC count}}$	Hb per RBC
MCHC (Mean Corpuscular Hemoglobin Concentration)	$\text{MCHC} = \frac{\text{Hemoglobin} \times 100}{\text{Hematocrit}}$	Hb concentration in RBCs

• Terminology:

  • Microcytic / Macrocytic / Normocytic: cell size

  • Hypochromic / Hyperchromic / Normochromic: Hb color intensity

8. Crime Scene Blood Detection

Forensic tests can detect blood at crime scenes.

• Luminol: Reacts with iron in hemoglobin → emits blue glow.

• Interfering substances: Bleach, metals, some cleaning products.

Lab 3: Blood Clotting, White Blood Cells, & Immunity

1. Blood Clotting

Blood clotting (hemostasis) prevents blood loss after injury.

• Intrinsic Pathway: Begins inside blood vessel (exposure to collagen).

• Extrinsic Pathway: Triggered by tissue damage and tissue factor.

• Both activate Factor X → Common Pathway:

  1. Prothrombin (II) → Thrombin (IIa)

  2. Fibrinogen (I) → Fibrin (Ia)

  3. Factor XIII stabilizes fibrin clot.

• Disorder: Hemophilia (missing clotting factor).

• Treatment: Plasma transfusions or recombinant clotting factors.

• Plasma vs Serum: Serum = plasma without clotting factors.

2. Immune System

The immune system defends against pathogens and abnormal cells.

• Innate Immunity: Fast, nonspecific (skin, macrophages, inflammation).

• Autoimmune Diseases: Type 1 diabetes, lupus, pernicious anemia (immune system attacks self).

3. Leukocytes

White blood cells are classified by their appearance and function.

• Granulocytes:

  • Neutrophils: Phagocytosis; most abundant.

  • Eosinophils: Attack parasites, mediate allergies.

  • Basophils: Release histamine, promote inflammation.

• Agranulocytes:

  • Monocytes → Macrophages: Phagocytosis, antigen presentation.

  • Lymphocytes:

    • B cells: Produce antibodies.

    • T cells: Cytotoxic (kill infected cells), helper (activate others), regulatory, memory.

Antigens vs Antibodies

• Antigens: Foreign molecules triggering immune response.

• Antibodies: Proteins that bind specific antigens; can cause agglutination, neutralization, or precipitation.

• 5 antibody classes:

  • IgG (2 binding sites): long-term immunity

  • IgA (4): mucosal surfaces

  • IgM (10): first response

  • IgE (2): allergies, parasites

4. Vaccination vs Immunization

• Vaccination: Administration of antigen (vaccine).

• Immunization: Development of immunity (result).

5. Tissue Typing & Blood Groups

• Antigens on RBCs:

  • Type A = A antigen, anti-B antibody

  • Type B = B antigen, anti-A antibody

  • Type AB = A & B antigens, no antibodies (universal plasma donor)

  • Type O = no antigens, both antibodies (universal donor for RBCs)

• Rh factor: + has antigen, – lacks it.

• Agglutination Test: Antibody causes visible clumping with matching antigen.

• Minimum antibodies for typing: Anti-A, Anti-B, Anti-Rh.

Lab 4: Endocrine System

1. Overview

The endocrine system is a network of glands that secrete hormones into the bloodstream to regulate metabolism, growth, reproduction, and homeostasis. Unlike the nervous system (which acts quickly and locally), endocrine signaling is slower but longer-lasting.

2. Major Endocrine Glands and Hormones

Gland	Hormones Produced	Primary Functions
Anterior Pituitary (Adenohypophysis)	GH, TSH, ACTH, LH, FSH, PRL	Stimulates target glands and tissues
Posterior Pituitary (Neurohypophysis)	ADH (vasopressin), Oxytocin	ADH controls water balance; oxytocin triggers uterine contractions and milk release
Thyroid	T3, T4 (thyroid hormones), Calcitonin	Regulates metabolism, growth, and calcium storage
Parathyroid	PTH	Increases blood calcium levels via bone resorption, renal reabsorption, and activation of vitamin D
Adrenal Cortex	Mineralocorticoids (aldosterone), glucocorticoids (cortisol), androgens	Aldosterone regulates Na+ & K+; cortisol manages stress, metabolism, and immune response
Adrenal Medulla	Epinephrine, Norepinephrine	Sympathetic "fight or flight" response
Pancreas	Insulin, Glucagon, Somatostatin	Regulates blood glucose levels
Gonads (Ovaries/Testes)	Estrogen, Progesterone, Testosterone	Control reproductive cycles, gamete development, and secondary sex traits
Pineal Gland	Melatonin	Regulates circadian rhythms

3. Hormone Classifications

• Peptide/Protein Hormones: Hydrophilic; bind to surface receptors → activate second messengers (e.g., insulin, ADH, GH).

• Steroid Hormones: Hydrophobic; derived from cholesterol; diffuse through membrane → bind intracellular receptors (e.g., cortisol, aldosterone, sex hormones).

• Amino Acid Derivatives: Derived from tyrosine (e.g., thyroid hormones, catecholamines).

Cortisol Negative Feedback Example

Structure	Hormone	Target	Effect
Hypothalamus	CRH	Anterior Pituitary	Stimulates ACTH release
Anterior Pituitary	ACTH	Adrenal Cortex	Stimulates cortisol production
Adrenal Cortex	Cortisol	Target tissues (liver, fat, muscle)	Increases glucose production, suppresses inflammation
Negative Feedback: Cortisol inhibits CRH and ACTH secretion.

5. Blood Glucose Regulation

• High blood sugar: Pancreas secretes insulin → promotes glucose uptake and glycogen synthesis → blood glucose decreases.

• Low blood sugar: Pancreas secretes glucagon → stimulates glycogen breakdown and gluconeogenesis → blood glucose increases.

• Glucose Tolerance Test: Measures how well the body handles a glucose load. A neural factor was not measured—it's purely hormonal and metabolic.

6. Steroid vs. Peptide Hormones

Feature	Steroid Hormones	Peptide Hormones
Structure	Lipid-based (cholesterol)	Amino acid chains
Solubility	Hydrophobic	Hydrophilic
Receptor Location	Intracellular/nuclear	Cell membrane
Transport	Bound to carrier proteins	Free in plasma

7. Clinical Links

• Hyperthyroidism: Excess thyroid hormone → increased metabolism, heat intolerance, weight loss.

• Hypothyroidism: Low thyroid hormone → fatigue, cold intolerance, weight gain.

• Cushing's Syndrome: Excess cortisol → hyperglycemia, fat redistribution, muscle wasting.

• Addison's Disease: Low cortisol and aldosterone → fatigue, low BP, electrolyte imbalance.

• Diabetes Mellitus: Insulin deficiency (Type 1) or resistance (Type 2) → elevated blood glucose.

Lab 5: Nervous System

1. Nervous vs. Endocrine Systems

Feature	Nervous System	Endocrine System
Signal Type	Electrical + chemical	Chemical (hormones)
Transmission Speed	Fast (milliseconds)	Slow (seconds to days)
Duration	Short-lived	Long-lasting
Control	Voluntary & involuntary	Involuntary
Distance	Local (synaptic)	Long (bloodstream)

2. Neural Tissue

Neural tissue consists of neurons and supporting cells (neuroglia).

• Neurons: Transmit electrical impulses; consist of cell body, dendrites, axon.

• Neuroglia: Support, protect, and nourish neurons.

3. Action Potentials & Membrane Potential

Neurons communicate via action potentials, rapid changes in membrane potential.

• Resting Membrane Potential: Typically –70 mV; maintained by Na+/K+ pumps.

• Action Potential Steps:

  1. Depolarization: Na+ channels open, Na+ enters, inside becomes positive.

  2. Repolarization: K+ channels open, K+ exits, inside becomes negative again.

• Nodes of Ranvier: Gaps in myelin where action potentials jump (saltatory conduction).

4. Neuroanatomy & Synapses

Neurons are organized into networks for sensory and motor functions.

• Excitatory neurotransmitters: e.g., Acetylcholine (ACh).

• Synapse: Junction between neurons for signal transmission.

5. Sensory Systems

Sensory systems detect and process environmental stimuli.

• Receptor → Sensory neuron → Integration center (CNS) → Motor neuron → Effector

• Reflex arc: Simple neural pathway for rapid response.

• Pupil reflex: Example of a complex reflex; involves multiple neurons.

6. Myelinated vs. Unmyelinated Axons

• Myelinated axons: Faster conduction due to saltatory conduction.

• Unmyelinated axons: Slower conduction.

• Gray matter: Cell bodies, dendrites.

• White matter: Myelinated axons.

7. Brain & Spinal Cord Organization

• Brain: Base contains vital centers (e.g., for breathing, heart rate).

• Spinal cord: Transmits signals between brain and body.

8. Clinical Relevance

• Multiple sclerosis: Demyelination disease affecting CNS.

• Guillain-Barré syndrome: Demyelination disease affecting PNS.