Lecture Notes: Cell Specialization and Differentiation

Introduction

• Discussion on cell specialization and differentiation.
• Importance of specific cell adaptations for performing specialized functions.

Cell Surface Area to Volume Ratio

• Cells need a threshold of surface area to volume ratio to maintain homeostasis.
• High surface area to volume ratio is beneficial for efficient function.

Examples of Specialized Cells

Red Blood Cells

• Function: Transport nutrients efficiently.
• Shape: Biconcave disc, which increases surface area to volume ratio.
• Allows for efficient nutrient transfer.

Cells in the Kidney's Proximal Convoluted Tubule

• Function: Reabsorb nutrients like glucose, vitamins, electrolytes.
• Structure: One cell thick, with microvilli and invaginations to increase surface area.

Lung Specialization

Alveoli Cells

• Two types: Type 1 and Type 2 pneumocytes.
• Type 1: Thin, wide, support gas exchange.
• Type 2: Cuboidal shape, secrete surfactant to reduce surface tension and prevent alveolar collapse.

Muscle Cells

Skeletal Muscle

• Function: Voluntary movement.
• Structure: Long, striated cells with many nuclei.
• Myofibrils enable contraction.

Cardiac Muscle

• Function: Heart contraction.
• Structure: Shorter cells, usually one nucleus.
• Connected via intercalated discs to synchronize contraction.

Reproductive Cells

Egg Cells

• Function: Support and develop fertilized zygote.
• Large with many macromolecules.
• Plasma membrane changes upon fertilization to prevent other sperm entry.

Sperm Cells

• Function: Fertilization of egg.
• Small with tail packed with mitochondria for movement.
• Head contains enzymes to penetrate egg’s outer layer.

Conclusion

• Overview of the importance of specialization and differentiation in various cells for their specific functions.
• Essential to understand these specializations for exams, focusing on differences between cell types and their adaptations.