Physiology & Embryology: Lymphatics, Integumentary System, and Cancer Biology

These flashcards cover the lymphatic system anatomy and fluid balance, the structures and functions of the integumentary system layers/appendages, and the fundamental principles of cancer biology including nomenclature, hallmarks, and staging.

What are the primary functions of the lymphatic system?

Immune function, fluid balance, and transport of lipids, hormones, and cytokines.

How is lymph fluid returned to the systemic venous blood?

It diffuses into lymphatic vessels and is carried to the lymph nodes and then into either the Right lymphatic duct or the Thoracic duct (Lt).

What provides the p医eess for the pumpless lymphatic system to ensure one-way flow toward the heart?

A series of valves, combined with compression from skeletal muscle contraction, pulsating expansion of nearby arteries, and contraction of smooth muscles in lymphatic vessel walls.

What is the primary composition of lymph?

Primarily water and small amounts of dissolved proteins, mostly albumin.

What percent of the total blood volume is held in the skin's blood reservoir?

$5\%\text{ of Blood Volume}$.

What are the three main layers of the skin?

The Epidermis (outer layer), Dermis (‐true‐ skin), and Hypodermis (subcutaneous layer).

List the five layers of the epidermis from deepest to most superficial.

$1.$ Stratum Basale (Stratum Germinativum), $2.$ Stratum Spinosum, $3.$ Stratum Granulosum, $4.$ Stratum Lucidum (thick skin only), and $5.$ Stratum Corneum.

What is the function of Langerhans cells?

They are star-shaped dendritic cells (Antigen Presenting Cells) that originate in the bone marrow and play a major role in the skin’s immune system.

Which sensory receptor is responsible for rapid-adapting touch sensation in the dermis?

Meissner’s corpuscles.

Distinguish between the Papillary and Reticular layers of the dermis.

The Papillary layer is thin, superficial, and contains dermal papillae; the Reticular layer is deep, contains dense irregular connective tissue, and makes up approximately $80\%\text{ of the thickness}$.

What causes the formation of fingerprints?

Sweat from pores outlining the pattern of epidermal ridges on the palms and soles.

What is the role of the Arrector pili muscle?

It is a smooth muscle attached to hair follicles under sympathetic nervous system control that pulls hair vertical in response to cold or fear.

Define the difference between Eccrine and Apocrine sweat glands.

Eccrine glands are found throughout the body and regulate temperature; Apocrine glands are larger, found in axillary and anogenital areas, and begin functioning at puberty.

What clinical indicator is described by the term ‐ecchymosis‐?

Bruising.

What is the Greek origin of the word ‐cancer‐?

Karkinoma, meaning crab.

Compare the mitotic index of benign versus malignant tumors.

Benign tumors have a Low mitotic index, while Malignant tumors have a High mitotic index.

What is Carcinoma in situ (CIS)?

Preinvasive epithelial malignant tumors that have not broken through the basement membrane or invaded the surrounding stroma.

How are malignant tumors arising from mesenchymal tissue classified?

Sarcoma.

What is the function of the tumor-suppressor gene TP53?

It monitors DNA integrity and can trigger $G_1\text{ arrest}$, DNA repair, or apoptosis (programmed cell death) if repair fails.

What is the ‐Warburg effect‐ in cancer biology?

The use of glycolysis under normal oxygen conditions (aerobic glycolysis) to allow products to be used for rapid cell growth.

Which infectious agent is associated with gastric adenocarcinoma and MALT lymphoma?

Helicobacter pylori.

In the WHO TNM staging system, what do the letters T, N, and M represent?

$T = \text{Primary tumor spread (size/extent)}$, $N = \text{Lymph node involvement}$, and $M = \text{Presence of distant metastasis}$.

Define the syndrome of cachexia.

The most severe form of malnutrition, characterized by anorexia, weight loss, anemia, asthenia, and altered protein, lipid, and carbohydrate metabolism.

What is the Epithelial-Mesenchymal Transition (EMT)?

A model for transition to metastatic cancer where cells lose epithelial characteristics and gain increased migratory capacity and resistance to apoptosis.